Haemostasis and Clotting Mechanisms

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Questions and Answers

What is the main purpose of haemostasis?

To prevent and control bleeding while maintaining blood fluidity (correct)

To increase blood viscosity after injury

To enhance blood flow to injured areas

To promote excessive bleeding during injury

Which elements form the clotting trilogy?

Blood vessels, platelets, and coagulation factors (correct)

Red blood cells, white blood cells, and plasma

Endothelial cells, fibroblasts, and growth factors

Vasoconstrictors, platelets, and fibrinolytic factors

What is primary haemostasis?

The maintenance of normal blood flow during injury

The initial response to vessel injury involving a platelet plug (correct)

The interaction of fibrin strands to strengthen a clot

The process that removes clots after vessel healing

What role does fibrin play in secondary haemostasis?

It reinforces and stabilizes the primary clot Signup and view all the answers

What is fibrinolysis?

The process of degrading the fibrin clot once healing is complete Signup and view all the answers

Which layer of the blood vessel wall is responsible for regulating vascular tone?

Media Signup and view all the answers

What is the primary function of the adventitia layer in blood vessels?

To provide structural support and protection Signup and view all the answers

What is the role of the intima in blood vessels?

To provide a smooth lining for blood flow Signup and view all the answers

What initiates the extrinsic pathway of the coagulation cascade?

Tissue factor binding to proenzyme factor VII Signup and view all the answers

What is the primary role of the TF-FVIIa complex in coagulation?

Activates factor X Signup and view all the answers

What does factor Xa do in the context of the extrinsic pathway?

Converts prothrombin to thrombin Signup and view all the answers

Which component is NOT part of the extrinsic prothrombinase complex?

Vitamin K Signup and view all the answers

What is the function of calcium ions (Ca²⁺) in the coagulation cascade?

Facilitate the formation of complexes Signup and view all the answers

What role does factor Va (FVa) serve in the coagulation process?

Acts as a co-factor for factor Xa Signup and view all the answers

Which of the following is a natural inhibitor of the coagulation process?

Antithrombin Signup and view all the answers

How does protein C act as an inhibitor in coagulation?

Inactivates factors Va and VIIIa Signup and view all the answers

What is the main storage location of vitamin B12 in the body?

Liver Signup and view all the answers

What characterizes megaloblastic anemia?

Delayed nuclear maturation of erythroblasts Signup and view all the answers

What is a major cause of megaloblastic anemia?

Deficiencies of vitamin B12 or folate Signup and view all the answers

What occurs during the amplification stage of coagulation?

Generation of additional thrombin Signup and view all the answers

What is the main role of thrombin in the coagulation process?

Promotes platelet activation and fibrinogen conversion Signup and view all the answers

What is the primary source of vitamin B12 for animals?

Microbial synthesis Signup and view all the answers

How is a factor assay result interpreted?

Using a reference curve of standard human plasma Signup and view all the answers

Which type of inhibitors are known to lose activity over time?

Time-dependent inhibitors Signup and view all the answers

What is a Bethesda Unit (BU) used to measure?

The strength of an inhibitor in plasma Signup and view all the answers

What is the purpose of the Ristocetin Cofactor assay?

To determine the functional activity of vWF Signup and view all the answers

What symptoms are commonly associated with bleeding disorders?

Epistaxis and heavy menstrual bleeding Signup and view all the answers

In which scenario does a deficiency of a specific factor manifest during a factor assay?

The plasma cannot compensate for the absent factor Signup and view all the answers

Which of the following factors are vitamin K-dependent?

Factors II, VII, IX, and X Signup and view all the answers

What is the role of gamma-carboxylation in the vitamin K cycle?

It allows for calcium ion binding in proteins Signup and view all the answers

What is a common cause of vitamin K deficiency?

Malabsorption of fat-soluble vitamins Signup and view all the answers

Which conditions are classified as acquired bleeding disorders?

Vitamin K deficiency and liver disease Signup and view all the answers

How does vitamin K deficiency affect clotting times?

It prolongs PT and APTT Signup and view all the answers

What type of assay is used to detect Factor VIII inhibitors?

Bethesda Assay Signup and view all the answers

What happens to vitamin K-dependent factors in the body during vitamin K deficiency?

They remain stable but ineffective Signup and view all the answers

What are the three main components of haemostatic mechanisms?

Primary haemostasis, secondary haemostasis, and fibrinolysis Signup and view all the answers

What is the primary role of von Willebrand factor (vWF) in haemostasis?

To facilitate platelet adhesion to injury sites Signup and view all the answers

How is the platelet plug primarily formed?

Through the formation of fibrin bridges between platelets Signup and view all the answers

What initiates the process of secondary haemostasis?

The exposure of subendothelial collagen Signup and view all the answers

Which statement best describes thromboxane A2's role in procoagulation?

It binds to platelet receptors, promoting aggregation Signup and view all the answers

Where is von Willebrand factor (vWF) primarily produced?

In Weibel-Palade bodies of endothelial cells Signup and view all the answers

What benign role does protein C serve in anticoagulation?

It inactivates coagulation factors Va and VIIIa Signup and view all the answers

How is fibrinolysis inhibited during the procoagulation process?

By the activity of plasminogen activator inhibitor-1 (PAI-1) Signup and view all the answers

What is the role of tissue factor in the coagulation process?

It initiates the coagulation cascade Signup and view all the answers

Which factor is crucial for the localized activation of coagulation factors?

Calcium ions (Ca²⁺) Signup and view all the answers

What is the structure of von Willebrand factor (vWF)?

A large multimeric glycoprotein Signup and view all the answers

How does protein S function in the anticoagulation pathway?

It acts as a co-factor for protein C Signup and view all the answers

Why is it important for the coagulation factor activation to occur at membrane surfaces?

It prevents the activation of all circulating factors simultaneously Signup and view all the answers

What is indicated by increased levels of serum methylmalonic acid (MMA)?

Vitamin B12 deficiency Signup and view all the answers

What do normal levels of both methylmalonic acid and homocysteine suggest?

Clinically significant B12 deficiency is ruled out Signup and view all the answers

What is the gold standard test for determining the cause of B12 deficiency?

Schilling test Signup and view all the answers

What is the first step in the Schilling test?

Giving an intramuscular injection of vitamin B12 Signup and view all the answers

Which of these is a main cause of B12 deficiency?

Autoimmune attack on gastric mucosa Signup and view all the answers

Why is folic acid often administered with B12 treatment?

To address potential folate deficiency Signup and view all the answers

What is a possible consequence of pancreatic enzyme insufficiency?

Inability of intrinsic factor to bind B12 Signup and view all the answers

Which condition is NOT associated with folate deficiency?

Congenital lack of intrinsic factor Signup and view all the answers

What does a blood test showing macrocytic cells typically indicate?

Vitamin B12 or folate deficiency Signup and view all the answers

What is the primary role of reticuloendothelial macrophages in relation to iron?

Supply of iron for hemoglobin synthesis Signup and view all the answers

Which of the following is NOT a mechanism by which anemia can occur?

Increased red blood cell formation Signup and view all the answers

What is a common factor in cases of folate deficiency?

Long-term use of certain antibiotics Signup and view all the answers

What is the primary function of transferrin in the body?

To deliver iron to developing erythroid precursors Signup and view all the answers

Which vitamin is primarily associated with the absorption issues identified in the Schilling test?

Vitamin B12 Signup and view all the answers

What dietary inclusions are recommended for increasing B12 intake?

Red meat, fish, and dairy Signup and view all the answers

Where is the majority of stored iron primarily found in the body?

In liver hepatocytes Signup and view all the answers

What is the primary mechanism by which dietary iron is absorbed in mammals?

Via the duodenal epithelium of the small intestine Signup and view all the answers

How is ferric iron (Fe³⁺) converted to ferrous iron (Fe²⁺) for absorption?

Through enzymatic reduction by duodenal cytochrome b Signup and view all the answers

Which of the following statements regarding hepcidin is accurate?

It is the master regulator of iron metabolism Signup and view all the answers

What effect does a transferrin saturation of less than 20% indicate?

Iron deficiency Signup and view all the answers

What factors are assessed in an extrinsic pathway factor assay?

Factors II, VII, and X Signup and view all the answers

Which factor does NOT influence hepcidin synthesis?

Exercise Signup and view all the answers

What does it suggest if both PT and APTT are prolonged?

A defect in the common clotting pathway Signup and view all the answers

What are the characteristic features observed in a blood film of an individual with iron deficiency anemia?

Microcytic and hypochromic red blood cells Signup and view all the answers

How is the total iron-binding capacity (TIBC) measured?

By saturating transferrin with a predetermined amount of iron Signup and view all the answers

What is the primary diagnostic application of a D-dimer test?

To exclude thromboembolic events Signup and view all the answers

What condition can lead to a prolonged APTT?

Factor deficiencies Signup and view all the answers

What is the standard oral treatment regimen for iron deficiency anemia (IDA)?

200 mg ferrous sulfate taken twice daily Signup and view all the answers

What does the Perls stain test specifically assess?

Haemosiderin stores in bone marrow Signup and view all the answers

How is thrombin time (TT) prolonged?

In patients with heparin therapy Signup and view all the answers

What happens to zinc protoporphyrin levels in iron deficiency anemia?

They will increase Signup and view all the answers

What does a normal PT with an abnormal APTT suggest?

A defect in the intrinsic pathway Signup and view all the answers

What is a limitation of the bleeding time test?

It is operator-dependent Signup and view all the answers

Which of the following is NOT a form of stored iron in the body?

Transferrin Signup and view all the answers

Which mechanism primarily leads to iron overload in the body?

Increased dietary intake of iron Signup and view all the answers

What does a mixing study indicate if the APTT corrects?

A factor deficiency Signup and view all the answers

What is required for the Clauss fibrinogen test?

A reference plasma with known fibrinogen levels Signup and view all the answers

In which condition are D-dimers raised?

Thromboembolic diseases Signup and view all the answers

What condition is indicated by a prolonged APTT and normal PT?

Intrinsic pathway defect Signup and view all the answers

What treatment options are available for patients who cannot tolerate or are unresponsive to oral iron?

Parenteral iron treatment via IV or IM Signup and view all the answers

What indicates the presence of lupus anticoagulant when performing a mixing study?

No correction in APTT Signup and view all the answers

What is the function of a Clauss fibrinogen test?

To measure fibrinogen levels in plasma Signup and view all the answers

What is a significant risk associated with parenteral iron treatment?

High cost and potential side effects Signup and view all the answers

When is a blood transfusion warranted for patients with iron deficiency anemia (IDA)?

For patients with symptomatic anemia unresponsive to iron therapy Signup and view all the answers

What factor deficiencies cannot be detected by APTT?

Factor VII and XIII Signup and view all the answers

What indicates a positive response to IDA treatment?

Hemoglobin returns to normal after 2-4 months Signup and view all the answers

What does a dimorphic blood film signify during treatment for IDA?

Response to therapy with mixed cell morphology Signup and view all the answers

What does primary haemostatic testing primarily assess?

Platelet function Signup and view all the answers

What substance do chief cells in the stomach secrete that is crucial for protein digestion?

Pepsin Signup and view all the answers

Which test is commonly used in secondary haemostatic testing?

Prothrombin Time (PT) Signup and view all the answers

What is critical in sample collection for coagulation tests?

Adding sodium citrate as an anticoagulant Signup and view all the answers

What happens to vitamin B12 after it binds to R-protein in the stomach?

It remains unabsorbed until digestion of R-protein occurs. Signup and view all the answers

What happens if poor venepuncture technique is used during sample collection?

Sample contamination can introduce tissue factor Signup and view all the answers

Why is intrinsic factor (IF) essential for vitamin B12 absorption?

B12-IF complexes are required for absorption in the intestines. Signup and view all the answers

What occurs to vitamin B12 after being absorbed in the terminal ileum?

It binds to transcobalamin for transport. Signup and view all the answers

What do platelet function assays evaluate?

The process of platelet adhesion and aggregation Signup and view all the answers

What is the typical sample volume needed for platelet function assays?

800 µL of whole blood in sodium citrate Signup and view all the answers

What percentage of vitamin B12 can be absorbed in the absence of intrinsic factor?

1% Signup and view all the answers

Which condition is NOT evaluated by the prothrombin time (PT) test?

Fibrinogen levels Signup and view all the answers

How does folate deficiency develop compared to vitamin B12 deficiency?

More rapidly due to a faster turnover rate. Signup and view all the answers

What is a hallmark feature of megaloblastic anaemia observed in neutrophils?

Hypersegmented neutrophils Signup and view all the answers

How is the INR (International Normalized Ratio) calculated?

Patient PT divided by normal PT multiplied by ISI Signup and view all the answers

What does an INR greater than 5.0 indicate?

High risk of bleeding requiring urgent assessment Signup and view all the answers

What complication can arise due to a deficiency in transcobalamin despite adequate vitamin B12 intake?

Megaloblastic anaemia Signup and view all the answers

What happens to folate once it enters the cell?

It is converted to folate polyglutamates. Signup and view all the answers

What causes hypersegmented neutrophils in megaloblastic anaemia?

Delayed DNA synthesis with intact segmentation mechanism. Signup and view all the answers

How are serum iron and ferritin levels typically affected in megaloblastic anaemia?

Both are normal. Signup and view all the answers

What is macrocytosis and how is it related to B12 deficiency?

Enlarged red blood cells indicating early B12 deficiency. Signup and view all the answers

Why is there an increase in serum unconjugated bilirubin in megaloblastic anaemia?

Breakdown of marrow cells leads to increased bilirubin. Signup and view all the answers

What happens to serum homocysteine levels in individuals with both B12 and folate deficiency?

They increase significantly. Signup and view all the answers

What is the first clotting factor to be reduced in liver disease?

Factor VII (FVII) Signup and view all the answers

What condition is characterized by the depletion of clotting factors and platelets due to ongoing clot formation?

Disseminated Intravascular Coagulation (DIC) Signup and view all the answers

What is considered massive hemorrhage in terms of blood loss within three hours?

Blood loss >50% of circulating volume Signup and view all the answers

What is the main consequence of untreated Disseminated Intravascular Coagulation (DIC)?

Increased risk of organ failure Signup and view all the answers

Which factor is contained in cryoprecipitate?

Factor XIII Signup and view all the answers

What triggers the production of thrombopoietin affecting platelet count?

Liver function Signup and view all the answers

How is Octaplas primarily different in terms of coagulation protein content?

Decreased Protein S levels Signup and view all the answers

Which condition can result from a deficiency of Factor VIII?

Hemophilia A Signup and view all the answers

What is the typical dosage of Fresh Frozen Plasma (FFP) administered?

15 mL/kg body weight Signup and view all the answers

What is a potential risk of transfusion during massive hemorrhage?

Bleeding to death Signup and view all the answers

What percentage of Haemophilia A patients develop inhibitors?

14% Signup and view all the answers

In which condition do autoantibodies commonly develop against clotting proteins?

Autoimmune conditions Signup and view all the answers

Which factor is deficient in Hemophilia C?

Factor XI Signup and view all the answers

What storage condition is required for thawed Fresh Frozen Plasma (FFP)?

At 4°C for 24 hours Signup and view all the answers

What is the primary site of haemopoiesis in adults?

Axial skeleton bone marrow Signup and view all the answers

Which of the following is NOT a stage of erythropoiesis?

Megakaryocyte Signup and view all the answers

What regulates the process of erythropoiesis?

Erythropoietin Signup and view all the answers

How long does it take for a red blood cell to develop from a stem cell?

7 days Signup and view all the answers

Which treatment is used to increase levels of von Willebrand factor?

Desmopressin (DDAVP) Signup and view all the answers

Which of the following is a symptom of platelet disorders?

Nosebleeds Signup and view all the answers

What are the stages of thrombopoiesis?

Megakaryoblast, Promegakaryocyte, Megakaryocyte, Platelets Signup and view all the answers

What characterizes von Willebrand Disease?

Autosomal dominant bleeding disorder Signup and view all the answers

What might increase the risk of infection and thrombosis in haemophilia treatment?

Portacath access Signup and view all the answers

Which type of vWD involves total vWF deficiency?

Type 3 Signup and view all the answers

What is the role of von Willebrand factor (vWF) in blood coagulation?

Protects Factor VIII from degradation Signup and view all the answers

What is a common cause of quantitative platelet disorders?

Decreased production of platelets Signup and view all the answers

Which growth factor is responsible for stimulating granulopoiesis?

Granulocyte-Colony Stimulating Factor (G-CSF) Signup and view all the answers

What is the primary outcome of myelofibrosis?

Bone marrow is replaced by fibrous tissue. Signup and view all the answers

What triggers the production of erythropoietin (EPO)?

Hypoxia in the kidneys. Signup and view all the answers

Which factor is primarily responsible for stimulating platelet production?

Thrombopoietin (TPO) Signup and view all the answers

What defines aplastic anemia?

Failure of the bone marrow to produce all blood cell types. Signup and view all the answers

Where is thrombopoietin (TPO) primarily produced?

Liver and kidneys Signup and view all the answers

What is the primary function of stromal cells in the bone marrow?

They provide structural support and secrete growth factors. Signup and view all the answers

What type of cells are derived from the lymphoid lineage?

B-cells Signup and view all the answers

Which condition is characterized by an overproduction of red blood cells?

Polycythemia vera Signup and view all the answers

What condition results in the bone marrow producing dysfunctional blood cells?

Myelodysplastic syndrome (MDS) Signup and view all the answers

What is the role of adhesion molecules in haemopoiesis?

They facilitate interactions of stem cells with the bone marrow niche. Signup and view all the answers

What role does the transcription factor Hypoxia-Inducible Factor (HIF) play in EPO production?

It activates genes that produce EPO in response to hypoxia. Signup and view all the answers

Which condition can lead to extramedullary haemopoiesis?

Myelofibrosis Signup and view all the answers

What is the primary characteristic of leukemia?

Overproduction of abnormal white blood cells. Signup and view all the answers

What are proplatelets?

Extensions from megakaryocytes that fragment to form platelets. Signup and view all the answers

What factor is crucial for neutrophil production?

Granulocyte-Colony Stimulating Factor (G-CSF) Signup and view all the answers

What is the role of the media layer in the blood vessel wall?

Regulates vascular tone and blood pressure Signup and view all the answers

What is the main purpose of fibrinolysis?

To degrade fibrin clots after healing is complete Signup and view all the answers

Which statement best describes primary haemostasis?

It involves blood vessels, platelets, and von Willebrand factor. Signup and view all the answers

What prevents bleeding from occurring as a normal bodily response?

Formation of a platelet plug Signup and view all the answers

What are the three layers of the blood vessel wall?

Intima, media, adventitia Signup and view all the answers

How does the adventitia layer contribute to blood vessels?

It provides structural support and anchors vessels. Signup and view all the answers

What is the significance of von Willebrand factor (vWF) in primary haemostasis?

It binds platelets to damaged blood vessel sites. Signup and view all the answers

What event marks the transition from primary to secondary haemostasis?

The interaction of coagulation factors to produce fibrin Signup and view all the answers

What initiates the common pathway in the coagulation cascade?

The generation of thrombin Signup and view all the answers

What happens when the extrinsic prothrombinase complex is formed?

It activates prothrombin to thrombin Signup and view all the answers

Which factor assists the thrombin-mediated activation of protein C?

Thrombomodulin Signup and view all the answers

What is the result of factor XIIIa's action on fibrin?

It catalyzes cross-link formation Signup and view all the answers

What best describes the role of the tenase complex in coagulation?

To activate factor X in the intrinsic pathway Signup and view all the answers

Which of these substances is NOT a naturally occurring inhibitor of coagulation?

Thrombomodulin Signup and view all the answers

What is a major cause of macrocytic anaemia?

Vitamin B12 deficiency Signup and view all the answers

Where is intrinsic factor (IF) secreted during the absorption of vitamin B12?

Stomach Signup and view all the answers

Which is NOT a component of the intrinsic tenase complex?

Factor Xa Signup and view all the answers

How does vitamin B12 contribute to DNA synthesis?

By serving as a co-factor for thymidine synthesis Signup and view all the answers

What is a characteristic feature of megaloblastic anaemia observed in the bone marrow?

Asynchronous maturation of erythroblasts Signup and view all the answers

Why is a short-term deficiency of vitamin B12 typically not problematic for the body?

The liver contains sufficient stores Signup and view all the answers

What does an increase in serum methylmalonic acid (MMA) indicate?

B12 deficiency Signup and view all the answers

Which step follows confirming low serum B12 levels in the investigation of macrocytic anemia?

Checking methylmalonic acid levels Signup and view all the answers

What role does FXIIIa play in preventing the degradation of clots?

It binds to α2-antiplasmin Signup and view all the answers

What is the percentage of young adult vegans reported to have subnormal vitamin B12 levels?

50% Signup and view all the answers

What is a likely cause of B12 deficiency associated with intrinsic factor?

Autoimmune attack on gastric mucosa Signup and view all the answers

Which test is considered the gold standard for assessing B12 absorption?

Schilling test Signup and view all the answers

What indicates a deficiency in intrinsic factor during the Schilling test?

Radiolabelled B12 present in urine after Step 2 Signup and view all the answers

What does the presence of radiolabelled B12 in urine after administering antibiotics indicate?

Bacterial overgrowth in the terminal ileum Signup and view all the answers

What is a primary dietary recommendation to treat B12 deficiency?

Increase intake of B12-rich foods Signup and view all the answers

Which is a common cause of folate deficiency?

Chronic digestive tract diseases Signup and view all the answers

What is the primary mechanism leading to the reduction in RBC formation in anemia?

Bone marrow malfunction Signup and view all the answers

Why is folic acid often prescribed along with B12 treatment?

To address concurrent folate deficiency Signup and view all the answers

How is iron primarily supplied for new red blood cell synthesis?

Reticuloendothelial macrophages Signup and view all the answers

What is an indication of significant B12 deficiency in terms of MMA and homocysteine levels?

High levels of both MMA and homocysteine Signup and view all the answers

What is the primary role of transferrin in the body?

To deliver iron to developing erythroid precursors and other tissues Signup and view all the answers

How is dietary non-haem iron typically found before absorption?

Ferric iron (Fe³⁺) Signup and view all the answers

What happens to ferric iron (Fe³⁺) in the enterocytes after absorption?

It is reduced to ferrous iron (Fe²⁺) Signup and view all the answers

What is haemosiderin primarily composed of?

Aggregates of iron, carbohydrates, lipids, and proteins Signup and view all the answers

What role does hepcidin play in iron metabolism?

It negatively regulates iron transport Signup and view all the answers

What characterizes red blood cells in iron deficiency anaemia?

Microcytic and hypochromic Signup and view all the answers

Which factor influences hepcidin synthesis?

Infection and inflammation Signup and view all the answers

What does total iron-binding capacity (TIBC) measure?

The maximum amount of iron needed to saturate transferrin Signup and view all the answers

What would a transferrin saturation of less than 20% indicate?

Iron deficiency Signup and view all the answers

Which method is used to measure serum ferritin?

ELISA Signup and view all the answers

What is zinc protoporphyrin (ZPP)?

A metabolite formed during haem synthesis Signup and view all the answers

What is the recommended oral iron treatment for iron deficiency anaemia (IDA)?

200 mg ferrous sulfate taken twice daily Signup and view all the answers

What is the primary function of the Perls stain in medical diagnostics?

To evaluate iron stores in bone marrow Signup and view all the answers

How is serum iron typically measured?

By a colorimetric method with acidic reagents Signup and view all the answers

What is the primary role of tissue factor in the coagulation cascade?

To initiate the coagulation cascade by binding to factor VIIa Signup and view all the answers

How does thromboxane A2 contribute to the process of haemostasis?

By activating platelets and facilitating their aggregation Signup and view all the answers

What is the main function of protein S in the anticoagulation pathway?

To bind to activated platelets and act as a co-factor for protein C Signup and view all the answers

Why is secondary haemostasis important?

It strengthens the platelet plug with fibrin strands Signup and view all the answers

Which component is primarily responsible for the transitional step from primary to secondary haemostasis?

Fibrinogen Signup and view all the answers

What activates platelets during the process of adhesion following vessel injury?

Collagen exposure Signup and view all the answers

What is the primary mechanism by which vWF protects factor VIII (FVIII)?

By safeguarding it from proteolytic degradation Signup and view all the answers

What role does ADAMTS13 play in the regulation of von Willebrand factor (vWF)?

It cleaves and regulates the activity of vWF Signup and view all the answers

What triggers the process of fibrinolysis?

The completion of healing processes at the injury site Signup and view all the answers

Which of the following factors is critical for localized activation during the coagulation process?

Calcium ions (Ca²⁺) Signup and view all the answers

During which phase of the coagulation cascade does the intrinsic pathway operate?

In the absence of external triggers Signup and view all the answers

How is nitric oxide involved in the regulation of haemostasis?

It inhibits platelet function and acts as a vasodilator Signup and view all the answers

What do chief cells in the stomach primarily secrete?

Pepsin Signup and view all the answers

What binds vitamin B12 after it is freed from dietary proteins?

R-protein Signup and view all the answers

Where are vitamin B12-IF complexes absorbed in the digestive tract?

Terminal ileum Signup and view all the answers

What role does intrinsic factor (IF) play in the absorption of vitamin B12?

It protects B12 from bacterial degradation. Signup and view all the answers

What is the consequence of a lack of intrinsic factor in vitamin B12 absorption?

Partial absorption of vitamin B12 Signup and view all the answers

How does folate deficiency develop more rapidly than vitamin B12 deficiency?

Folate has a faster metabolic turnover rate. Signup and view all the answers

What is a hallmark feature of megaloblastic anaemia in neutrophils?

Presence of hypersegmented neutrophils Signup and view all the answers

What role does transcobalamin play in the body after vitamin B12 absorption?

It delivers B12 to bone marrow and tissues. Signup and view all the answers

What happens to homocysteine levels in the presence of both vitamin B12 and folate deficiency?

They increase Signup and view all the answers

What happens to vitamin B12 after it is absorbed in the terminal ileum?

It binds to transcobalamin and enters the bloodstream. Signup and view all the answers

Why does megaloblastic anaemia occur despite normal intake of vitamin B12?

Deficiency in transcobalamin Signup and view all the answers

What is the primary role of methionine synthetase in folate metabolism?

It converts methyl-THF to THF and methylates homocysteine. Signup and view all the answers

How does low red cell folate reflect folate status in the body?

It is a reliable indicator of tissue folate status. Signup and view all the answers

What is a potential risk associated with parenteral iron treatment?

High cost of treatment Signup and view all the answers

What does a dimorphic blood film during IDA treatment indicate?

A response to therapy with a mix of red blood cell types Signup and view all the answers

When are blood transfusions considered for IDA patients?

For symptomatic patients unresponsive to iron therapy Signup and view all the answers

Which of the following tests is NOT used for secondary haemostatic testing?

Platelet function assays Signup and view all the answers

What is a primary indicator that APTT is prolonged?

Deficiency in factors VIII, IX, or XI Signup and view all the answers

What can occur if poor venepuncture technique is used during sample collection for coagulation tests?

Introduction of tissue factor, activating the sample Signup and view all the answers

What is the purpose of the Clauss fibrinogen test?

To assess the levels of fibrinogen in plasma Signup and view all the answers

How does sodium citrate act as an anticoagulant during sample collection?

By removing calcium ions from the blood Signup and view all the answers

When is thrombin time (TT) typically prolonged?

In patients on heparin therapy Signup and view all the answers

What is the main purpose of using platelet function assays?

To evaluate platelet adhesion and aggregation Signup and view all the answers

What does it indicate if a mixing study does not correct APTT?

A lupus anticoagulant may be present Signup and view all the answers

What is measured during a D-dimer test?

The amount of fibrin degradation products Signup and view all the answers

What does an INR greater than 5.0 typically indicate?

A high risk of bleeding requiring urgent assessment Signup and view all the answers

Which of the following factors is NOT evaluated by prothrombin time (PT)?

Factor XIII Signup and view all the answers

What does a prolonged APTT and PT suggest?

A defect in the common clotting pathway Signup and view all the answers

What is the key limitation of bleeding time tests?

It is operator-dependent Signup and view all the answers

What is the correct order of draw for coagulation samples?

Second order of draw Signup and view all the answers

What is a characteristic finding in Bernard-Soulier Syndrome regarding platelet count?

Mild to moderate thrombocytopenia Signup and view all the answers

What does a 1:10 dilution represent in the Clauss fibrinogen test?

A standard for normal fibrinogen levels Signup and view all the answers

What does the prothrombin time (PT) test NOT assess?

Fibrinogen levels Signup and view all the answers

What conditions can lead to elevated D-dimer levels?

Thromboembolic diseases Signup and view all the answers

What happens to iron stores in patients undergoing effective treatment for iron deficiency anemia?

They can take up to 6 months to be fully replenished Signup and view all the answers

What does a normal thrombin time indicate?

Adequate fibrinogen conversion Signup and view all the answers

In factor assays, which factors are assessed in the intrinsic pathway?

Factors IX, XI, and XII Signup and view all the answers

What is a common use of mixing studies?

Diagnosing and differentiating APTT prolongation causes Signup and view all the answers

What may a prolonged bleeding time suggest?

Platelet dysfunction or low platelet count Signup and view all the answers

How do inhibitors in coagulation affect clotting times?

They neutralize or interfere with clotting factor function. Signup and view all the answers

Which of the following statements accurately describes the Bethesda Unit (BU)?

It measures the amount of inhibitor that neutralizes 50% of normal FVIII:C. Signup and view all the answers

What is the main reason for post-translational modification of vitamin K-dependent proteins?

To enable them to become functionally active. Signup and view all the answers

Which method is commonly used to measure the level of von Willebrand factor antigen?

Enzyme-Linked Immunosorbent Assay (ELISA) Signup and view all the answers

What is the primary function of Ristocetin in the vWF:RCo assay?

To induce platelet agglutination in the presence of functional vWF. Signup and view all the answers

Which condition is NOT associated with vitamin K deficiency?

Bone marrow failure. Signup and view all the answers

What characterizes secondary haemostatic defects compared to primary defects?

They often result in large bruises at unusual sites. Signup and view all the answers

What commonly causes a vitamin K deficiency in newborns?

Decreased vitamin K levels at birth. Signup and view all the answers

What happens to vitamin K-dependent factors in the case of vitamin K deficiency?

They become present but functionally inactive. Signup and view all the answers

Which of the following is a common symptom of bleeding disorders?

Joint bleeds. Signup and view all the answers

In which scenario is a factor assay result not interpretable?

In cases where a patient is deficient in a specific factor. Signup and view all the answers

Which of the following describes how latex immunoassays for vWF antigen work?

Latex particles agglutinate in presence of vWF, correlating turbidity to concentration. Signup and view all the answers

What are known as time-dependent inhibitors?

Inhibitors that degrade in activity as time progresses. Signup and view all the answers

What causes a decreased platelet count in liver disease?

Reduced production of thrombopoietin Signup and view all the answers

What does consumptive coagulation lead to?

Depletion of clotting factors and platelets Signup and view all the answers

What is the definition of massive hemorrhage?

Blood loss >50% of circulating volume within 3 hours Signup and view all the answers

Which blood components are lost during a massive hemorrhage?

Red blood cells, platelets, and coagulation factors Signup and view all the answers

When are platelet transfusions typically indicated?

For treatment of thrombocytopenia or platelet dysfunction Signup and view all the answers

What is the typical dosage for Fresh Frozen Plasma (FFP)?

15 mL/kg body weight Signup and view all the answers

What is the function of thrombin in DIC?

To convert fibrinogen to fibrin Signup and view all the answers

What are the possible causes of Disseminated Intravascular Coagulation (DIC)?

Infections, obstetric complications, malignancies, and widespread tissue damage Signup and view all the answers

What is the role of the F8 gene?

Codes for Factor VIII Signup and view all the answers

Which of the following does not typically characterize the consequences of DIC?

Hypercoagulability Signup and view all the answers

What is a major risk of untreated DIC?

Higher mortality due to uncontrolled bleeding and thrombosis Signup and view all the answers

What typically characterizes von Willebrand Disease (vWD)?

Excessive bleeding from minor wounds Signup and view all the answers

Which factor primarily regulates erythropoiesis?

Erythropoietin (EPO) Signup and view all the answers

What is the role of von Willebrand factor (vWF) in relation to Factor VIII?

Protects Factor VIII from degradation Signup and view all the answers

What is a symptom commonly associated with platelet disorders?

Prolonged bleeding after trauma Signup and view all the answers

How is a major component of thrombopoiesis regulated?

Thrombopoietin (TPO) Signup and view all the answers

What is a main cause of symptoms in individuals with Turner syndrome that can lead to hemophilia?

X-chromosome abnormalities Signup and view all the answers

Which factor affects the severity of bleeding in thrombocytopenia?

Underlying cause of platelet production failure Signup and view all the answers

What are the three distinct types of von Willebrand Disease?

Type 1, Type 2, Type 3 Signup and view all the answers

What is one of the benefits of prophylaxis over on-demand treatment for hemophilia?

It is less expensive Signup and view all the answers

What is the first stage of erythropoiesis?

Proerythroblast Signup and view all the answers

What treatment is used to increase levels of vWF and FVIII in patients with vWD?

DDAVP (Desmopressin) Signup and view all the answers

What is one of the risks associated with prophylaxis in hemophilia treatment?

Inhibitor development Signup and view all the answers

What triggers extramedullary haemopoiesis to occur?

Bone marrow failure or increased demand for blood cells Signup and view all the answers

What does M-CSF primarily regulate?

Monocyte production Signup and view all the answers

Which of the following cytokines stimulates the production of neutrophils?

Granulocyte-Colony Stimulating Factor (G-CSF) Signup and view all the answers

Which condition is characterized by a failure of the bone marrow to produce sufficient blood cells?

Aplastic anaemia Signup and view all the answers

During erythropoiesis, what is the primary role of reticulocytes?

They are immature red blood cells released into circulation Signup and view all the answers

What is the function of proplatelets in thrombopoiesis?

They are extensions from megakaryocytes that fragment to form platelets Signup and view all the answers

What is polycythaemia vera primarily characterized by?

Overproduction of red blood cells Signup and view all the answers

What role do adhesion molecules play in haemopoiesis?

They allow HSCs and progenitor cells to interact with the bone marrow niche Signup and view all the answers

What cytokine is primarily responsible for promoting B-cell development?

Interleukin-7 (IL-7) Signup and view all the answers

What is an autologous bone marrow transplant?

Using the patient’s own stem cells Signup and view all the answers

What do monocytes differentiate into during monocytopoiesis?

Macrophages and dendritic cells Signup and view all the answers

What is a common treatment used to manage neutropenia?

Granulocyte-Colony Stimulating Factor (G-CSF) Signup and view all the answers

What is the primary source of thrombopoietin (TPO) production?

Liver and kidneys Signup and view all the answers

What is the role of platelets during primary haemostasis?

They form a primary haemostatic plug through interactions with blood vessels. Signup and view all the answers

Which function is primarily associated with the media layer of the blood vessel wall?

Regulating vascular tone and blood pressure. Signup and view all the answers

How does fibrinolysis contribute to maintaining blood vessel health?

By degrading fibrin clots to prevent vascular occlusion. Signup and view all the answers

What is the significance of von Willebrand factor (vWF) in the haemostatic process?

It facilitates interactions between platelets and blood vessels. Signup and view all the answers

What occurs during secondary haemostasis?

Coagulation factors interact to generate fibrin strands. Signup and view all the answers

Which layer of the blood vessel wall provides protection and structural support?

Adventitia Signup and view all the answers

Why is fluidity maintenance of blood essential in normal bodily functions?

To ensure efficient nutrient transport. Signup and view all the answers

What is the main function of the intima layer in blood vessels?

To provide a smooth lining for blood flow. Signup and view all the answers

What do chief cells in the stomach secrete?

Pepsin Signup and view all the answers

What is the consequence of a deficiency in intrinsic factor (IF) related to vitamin B12?

Decreased absorption of vitamin B12 Signup and view all the answers

How is free vitamin B12 transported in the body after absorption?

Binds to transcobalamin Signup and view all the answers

What is the primary role of R-protein in vitamin B12 absorption?

Protecting vitamin B12 from enzymatic degradation Signup and view all the answers

Where does the B12-intrinsic factor (IF) complex get absorbed?

Terminal ileum Signup and view all the answers

Why do patients with megaloblastic anemia often have increased serum unconjugated bilirubin?

Breakdown of marrow cells Signup and view all the answers

What is the primary function of thrombomodulin in the anticoagulation process?

It reduces clot formation by binding thrombin Signup and view all the answers

What is the primary form in which non-haem dietary iron is found?

Ferric iron (Fe³⁺) Signup and view all the answers

What is the main effect of endothelial cells during procoagulation?

They release endothelin-1, causing vasoconstriction Signup and view all the answers

What is the effect of vitamin B12 deficiency on red blood cell production?

Decreased cell production Signup and view all the answers

What type of cells in the bone marrow are affected by deficiencies in vitamin B12 and folate?

Immature blasts Signup and view all the answers

What initiates the process of secondary haemostasis in the coagulation cascade?

Exposure of procoagulant material due to vessel injury Signup and view all the answers

What is the role of hepcidin in iron metabolism?

It degrades ferroportin, reducing iron transport. Signup and view all the answers

What is the typical serum ferritin level in iron deficiency anaemia (IDA)?

Decreased Signup and view all the answers

Which of the following statements about folate absorption is accurate?

Folate is absorbed as methyl-THF in the upper small intestine Signup and view all the answers

How does protein S enhance the function of protein C in anticoagulation?

By promoting the binding of activated protein C to phospholipids Signup and view all the answers

What is the main outcome of primary haemostasis?

Formation of a temporary platelet plug Signup and view all the answers

What factor would NOT lead to iron overload?

Iron deficiencies Signup and view all the answers

What occurs to serum homocysteine levels in the case of both vitamin B12 and folate deficiencies?

They increase Signup and view all the answers

What occurs to zinc protoporphyrin levels in iron deficiency?

Increased levels occur Signup and view all the answers

What role does tissue plasminogen play in the regulation of coagulation?

It activates plasminogen to promote clot lysis Signup and view all the answers

How do thromboxane A2 and platelet-activating factor (PAF) enhance the coagulation process?

They activate platelets by binding to von Willebrand factor on the endothelial wall Signup and view all the answers

What is a hallmark finding in the blood associated with megaloblastic anemia?

Hypersegmented neutrophils Signup and view all the answers

How is TIBC (total iron-binding capacity) typically affected in iron deficiency anaemia?

TIBC is elevated Signup and view all the answers

What is the main role of transcobalamin in relation to vitamin B12?

Transport of vitamin B12 to tissues Signup and view all the answers

What is a significant characteristic of von Willebrand factor (vWF) in relation to factor VIII?

It protects FVIII from proteolytic degradation Signup and view all the answers

What is the primary function of the Perls stain?

To assess haemosiderin stores Signup and view all the answers

What happens to vitamin B12 once it binds to intrinsic factor?

It forms a stable complex for absorption Signup and view all the answers

What is the main physiological function of prostacyclin in the context of haemostasis?

Inhibits platelet function and acts as a vasodilator Signup and view all the answers

What is not a characteristic feature of iron deficiency anaemia (IDA)?

Increased white blood cell count Signup and view all the answers

What mechanism inhibits fibrinolysis during procoagulation?

Release of Plasminogen Activator Inhibitor-1 (PAI-1) Signup and view all the answers

In what form is haem iron transported into the enterocyte?

By haem carrier protein 1 (HCP1) Signup and view all the answers

What happens to iron stored in haemosiderin?

Iron is released slowly and not readily available. Signup and view all the answers

What is the primary indication of normal levels of both methylmalonic acid and homocysteine?

Normal B12 and folate status Signup and view all the answers

What is the key role of fibrin in the coagulation process?

It strengthens the platelet plug Signup and view all the answers

What does the intrinsic pathway of coagulation primarily rely on?

Factors that are all present in plasma Signup and view all the answers

Which of the following is NOT a characteristic step in investigating macrocytic anaemia?

High homocysteine without elevated MMA Signup and view all the answers

What is a common cause of iron deficiency?

Insufficient dietary intake Signup and view all the answers

What is the gold standard test for assessing B12 absorption versus dietary intake?

Schilling test Signup and view all the answers

Which of the following statements is true regarding ferritin?

Ferritin is present in low concentrations in the plasma. Signup and view all the answers

What is the primary means through which the body loses iron?

Sloughing of skin cells and bleeding Signup and view all the answers

How does increased blood flow affect platelet rolling during vessel injury?

It promotes further platelets to interact via vWF Signup and view all the answers

What does the administration of intrinsic factor (IF) in Step 2 of the Schilling test help determine?

Intrinsic factor deficiency Signup and view all the answers

What happens to transferrin saturation levels in iron deficiency?

Falls below 20% Signup and view all the answers

What would the presence of radiolabelled B12 in the urine after Step 3 of the Schilling test indicate?

Bacterial overgrowth in the terminal ileum Signup and view all the answers

In which condition is pancreatic enzyme insufficiency likely to affect B12 absorption?

Chronic pancreatitis Signup and view all the answers

What could be a cause of folate deficiency?

Poor dietary intake Signup and view all the answers

Why is folic acid often administered alongside B12 treatment?

To manage potential folate deficiency Signup and view all the answers

What mechanism primarily supplies iron for new red blood cell synthesis?

Reticuloendothelial macrophages Signup and view all the answers

What is the main outcome of the activation of factor X (FX) in the coagulation cascade?

It cleaves prothrombin to thrombin. Signup and view all the answers

What factor is associated with both B12 and folate absorption issues?

Chronic digestive tract diseases Signup and view all the answers

What defines anaemia according to WHO standards in non-pregnant women over 15 years?

Haemoglobin levels below 120 g/L Signup and view all the answers

What initiates the amplification phase of coagulation?

The generation of thrombin. Signup and view all the answers

Which complex is primarily responsible for converting prothrombin to thrombin?

Prothrombinase complex. Signup and view all the answers

What are the two primary mechanisms that result in anaemia?

Reduction in RBC formation and reduced RBC survival Signup and view all the answers

What role does tissue factor pathway inhibitor (TFPI) play in coagulation?

It blocks the TF-FVIIa complex and the extrinsic pathway. Signup and view all the answers

What is the primary consequence of FXIIIa's action on fibrin?

It stabilizes the fibrin clot through cross-linking. Signup and view all the answers

What treatment options are available for patients who are intolerant or unresponsive to oral iron?

Parenteral iron treatment via IV infusion or IM injection Signup and view all the answers

How does factor IXa (FIXa) function within the coagulation cascade?

It assists in the formation of the tenase complex. Signup and view all the answers

What is the role of vitamin K in the coagulation process?

It is essential in the synthesis of prothrombin. Signup and view all the answers

What potential risks are associated with parenteral iron treatment?

High cost and potential side effects Signup and view all the answers

When is a blood transfusion considered for patients with iron deficiency anemia (IDA)?

For patients with symptomatic anemia unresponsive to iron therapy Signup and view all the answers

Which of the following is NOT a key role of thrombin in the coagulation cascade?

Activation of vitamin K. Signup and view all the answers

What signifies that a patient is responding to IDA treatment?

Reticulocyte count peaks at 1-2 weeks Signup and view all the answers

What is the significance of the intrinsic tenase complex?

It activates factor X at a higher efficiency than the extrinsic pathway. Signup and view all the answers

Where is antithrombin primarily produced?

Liver. Signup and view all the answers

What happens during the propagation phase of coagulation?

Formation of the tenase complex and amplification of thrombin generation. Signup and view all the answers

What are the common tests used in secondary haemostatic testing?

PT, APTT, and Fibrinogen levels Signup and view all the answers

Which anticoagulant is used in the collection of coagulation samples?

Sodium citrate Signup and view all the answers

What is the mechanism by which protein C acts to reduce coagulation?

It inactivates factors Va and VIIIa with protein S. Signup and view all the answers

How does sodium citrate act as an anticoagulant?

By removing calcium ions from the sample Signup and view all the answers

How long can the body store vitamin B12 without dietary intake?

3-4 years. Signup and view all the answers

What is the purpose of performing mixing studies in prolonged clotting time investigations?

To assess the presence of inhibitors or factor deficiencies Signup and view all the answers

What type of anaemia is primarily characterized by larger than normal red blood cells?

Megaloblastic anaemia. Signup and view all the answers

What does the prothrombin time (PT) evaluate in the coagulation cascade?

The extrinsic and common pathways of coagulation Signup and view all the answers

Which of the following conditions can lead to megaloblastic anaemia?

Vitamin B12 deficiency. Signup and view all the answers

Which of the following conditions can affect prothrombin time (PT)?

Liver disease Signup and view all the answers

What does an INR greater than 5.0 indicate regarding patient safety?

High risk of bleeding requiring urgent assessment Signup and view all the answers

How should platelet function assay samples be stored prior to testing?

At room temperature and delivered quickly Signup and view all the answers

What aspect of coagulation do optical coagulation analysers primarily measure?

Light absorbance and transmission Signup and view all the answers

What does a prolonged APTT indicate?

Defect in the intrinsic pathway or factor deficiencies Signup and view all the answers

In which scenario might PT and APTT both be prolonged?

Defect in the common clotting pathway Signup and view all the answers

What parameter does the Clauss fibrinogen test primarily measure?

Fibrinogen levels in plasma Signup and view all the answers

Which of the following conditions can lead to a prolonged APTT?

Heparin therapy Signup and view all the answers

When is a D-dimer test most commonly utilized?

To exclude thromboembolic events Signup and view all the answers

What would a normal thrombin time (TT) suggest?

Normal fibrin formation Signup and view all the answers

What does a mixing study that does not correct APTT indicate?

Presence of an inhibitor Signup and view all the answers

Which factors are particularly sensitive to APTT testing?

Factors VIII, IX, and XI Signup and view all the answers

Why is the thrombin time rarely performed in modern labs?

Availability of more precise tests Signup and view all the answers

What does a normal bleeding time indicate?

Normal platelet function and integrity of hemostasis Signup and view all the answers

What is the purpose of a factor assay?

To monitor factor replacement therapy Signup and view all the answers

What can elevated D-dimer levels indicate?

Increased clot formation and breakdown Signup and view all the answers

At what factor level can PT and APTT detect deficiencies?

When decreased to 25-40% of normal Signup and view all the answers

Which therapy is most likely to cause prolonged thrombin time?

Heparin therapy Signup and view all the answers

How does the presence of inhibitors affect the function of specific clotting factors?

They interfere with the normal function of clotting factors. Signup and view all the answers

What is the primary purpose of the Bethesda Assay?

To detect Factor VIII inhibitors. Signup and view all the answers

What do latex immunoassays (LIA) rely on for the detection of vWF antigen?

Agglutination of latex particles in the presence of vWF. Signup and view all the answers

What is a common symptom of primary haemostatic defects?

Epistaxis (nosebleeds). Signup and view all the answers

Which of the following conditions is an example of an inherited bleeding disorder?

Haemophilia. Signup and view all the answers

What condition can lead to the development of inhibitors in patients?

Recombinant factor therapy. Signup and view all the answers

Which vitamin K-dependent factor is involved in inhibiting coagulation?

Protein C. Signup and view all the answers

What does the Ristocetin Cofactor assay specifically measure?

The functional activity of von Willebrand factor. Signup and view all the answers

What happens to vitamin K-dependent factors during vitamin K deficiency?

They are present but non-functional. Signup and view all the answers

What is often observed in patients with secondary haemostatic defects?

Joint and soft tissue bleeds. Signup and view all the answers

What effect does gamma-carboxylation have on vitamin K-dependent proteins?

It enables them to bind to phospholipids. Signup and view all the answers

What treatment is given to newborns for vitamin K deficiency?

Vitamin K injections. Signup and view all the answers

What is a potential cause of vitamin K deficiency?

Use of oral anticoagulants like warfarin. Signup and view all the answers

What is the primary cause of decreased platelet count in liver disease?

Reduced production of thrombopoietin Signup and view all the answers

During massive hemorrhage, what component is NOT typically lost?

White blood cells Signup and view all the answers

What defines consumptive coagulation?

Depletion of clotting factors and platelets from continuous clot formation Signup and view all the answers

What is the storage duration for thawed Fresh Frozen Plasma (FFP)?

4 hours at room temperature Signup and view all the answers

Which of the following is a consequence of Disseminated Intravascular Coagulation (DIC)?

Thrombocytopenia Signup and view all the answers

What is a common trigger for the development of inhibitors in coagulation disorders?

Autoimmune conditions Signup and view all the answers

Which clotting factor is deficient in Hemophilia B?

Factor IX Signup and view all the answers

Octaplas differs from standard Fresh Frozen Plasma in that it has decreased levels of which protein?

Protein S Signup and view all the answers

What is the effect on fibrinogen levels following one adult therapeutic dose of cryoprecipitate?

Increases fibrinogen by 1 g/L Signup and view all the answers

Which of the following factors is part of the cryoprecipitate?

Factor VIII Signup and view all the answers

In terms of blood type compatibility, which of these is crucial for platelet transfusions?

ABO and RhD match where possible Signup and view all the answers

Which enzyme is involved in breaking down fibrin during DIC?

Plasmin Signup and view all the answers

What is the treatment strategy for managing DIC?

Treat the underlying cause and replacement therapy with blood products Signup and view all the answers

Which gene is located on the telomeric end of the X chromosome and associated with Hemophilia A?

F8 Signup and view all the answers

What is the most common inheritance pattern of von Willebrand Disease (vWD)?

Autosomal dominant Signup and view all the answers

What is one of the main risk factors associated with prophylactic treatment for haemophilia?

Increased risk of inhibitor development Signup and view all the answers

Which stage follows the proerythroblast in the process of erythropoiesis?

Basophilic erythroblast Signup and view all the answers

Which factor is essential for the differentiation of proerythroblasts into mature red blood cells?

Erythropoietin Signup and view all the answers

What is a common symptom of von Willebrand Disease?

Epistaxis (nosebleeds) Signup and view all the answers

What regulates thrombopoiesis in the body?

Thrombopoietin Signup and view all the answers

What causes quantitative platelet disorders?

Increased destruction of platelets Signup and view all the answers

Which type of von Willebrand Disease is characterized by total vWF deficiency?

Type 3 Signup and view all the answers

What is the role of von Willebrand factor in relation to Factor VIII?

Protects it from proteolytic degradation Signup and view all the answers

What growth factor stimulates granulopoiesis?

Granulocyte-Colony Stimulating Factor (G-CSF) Signup and view all the answers

What is one potential benefit of using plasma-derived clotting factors for haemophilia treatment?

Reduced cost compared to recombinant factors Signup and view all the answers

What cellular process describes the development of platelets from megakaryocytes?

Fragmentation Signup and view all the answers

What is the role of erythropoietin (EPO) in haemopoiesis?

Regulates red blood cell production Signup and view all the answers

What triggers the occurrence of extramedullary haemopoiesis?

Bone marrow failure or increased blood demand Signup and view all the answers

Which cytokine is primarily responsible for stimulating platelet production?

Thrombopoietin (TPO) Signup and view all the answers

What is myelofibrosis?

A disorder characterized by dense fibrous tissue in the bone marrow Signup and view all the answers

What cells differentiate from the myeloid lineage?

Erythrocytes and myeloblasts Signup and view all the answers

What does the presence of reticulocytes in circulation indicate?

Increased bone marrow activity Signup and view all the answers

Which condition is characterized by the failure of bone marrow to produce sufficient blood cells?

Aplastic anaemia Signup and view all the answers

What are the two types of bone marrow transplants?

Autologous and allogeneic Signup and view all the answers

What stimulates the production of monocytopoiesis?

Monocyte-Colony Stimulating Factor (M-CSF) Signup and view all the answers

What is a common symptom of polycythaemia vera?

Headache Signup and view all the answers

What effect does hypoxia have on erythropoietin (EPO) production?

Stimulates EPO production Signup and view all the answers

What is the primary function of granulocyte-colony stimulating factor (G-CSF)?

Stimulating neutrophil production Signup and view all the answers

Which condition is commonly treated with erythropoietin injections?

Severe anemia Signup and view all the answers

What is the most common stain used for blood films preparation in the UK?

May-Grunwald Giemsa (MGG) stain Signup and view all the answers

What might occur if a blood smear is prepared too thick?

Cell details cannot be seen clearly Signup and view all the answers

What is hypochromia in red blood cells indicative of?

Decreased hemoglobin content Signup and view all the answers

What is the normal myeloid-to-erythroid ratio in bone marrow?

2:1 to 4:1 Signup and view all the answers

What is the primary purpose of fixing a blood smear in methanol before staining?

To preserve cellular shape and morphology Signup and view all the answers

What happens to red blood cells when a smear is too thin?

Red blood cells appear as spherocytes Signup and view all the answers

What is the typical fixation time for bone marrow slides in methanol?

15-20 minutes Signup and view all the answers

Which white blood cell types can be identified on a stained smear?

Lymphocytes, Neutrophils, Monocytes, Eosinophils, Basophils Signup and view all the answers

What is the normal range for metamyelocytes?

2-13% Signup and view all the answers

What is the primary purpose of a bone marrow aspirate?

To assess cellular composition and abnormalities Signup and view all the answers

What microscopy technique is utilized for examining bone marrow aspirates?

Oil immersion microscopy Signup and view all the answers

What fixative is used for trephine biopsies?

10% formal saline Signup and view all the answers

What is indicated by the presence of tear-drop cells on a blood smear?

Myelofibrosis Signup and view all the answers

Which staining technique is used to assess iron stores in the bone marrow?

Perls’ Prussian Blue Signup and view all the answers

What does a positive Perls’ stain reveal?

Presence of iron Signup and view all the answers

What blood cell findings are typically associated with iron deficiency anaemia?

Microcytosis and hypochromia Signup and view all the answers

What indicates increased reticulin fibers in the bone marrow?

Bone marrow fibrosis Signup and view all the answers

Which condition is characterized by markedly hypocellular marrow and increased fat content?

Aplastic anaemia Signup and view all the answers

What color does PAS-positive material appear when stained?

Magenta or pink Signup and view all the answers

What is the normal cellularity range of bone marrow in adults?

30-70% Signup and view all the answers

What is typically observed in acute leukaemia on a bone marrow smear?

Increased numbers of myeloblasts or lymphoblasts Signup and view all the answers

What is the most critical step in the preparation of a blood film?

Spread the blood drop onto the slide Signup and view all the answers

What is the optimal duration for fixing a bone marrow slide in methanol?

15-20 minutes Signup and view all the answers

Which staining procedure is followed immediately after fixing in methanol in blood smear preparation?

Stain in May-Grunwald Signup and view all the answers

What does anisocytosis refer to in red blood cells?

Variation in the size of red blood cells Signup and view all the answers

What would be the appearance of red blood cells if a blood smear is too thin?

Red blood cells appear as spherocytes Signup and view all the answers

Which stage of a blood smear's preparation is performed after the slide is air dried?

Fixing with methanol Signup and view all the answers

Which staining method is NOT used for trephine biopsies?

Oil Red O Signup and view all the answers

What does a positive Perls’ Prussian Blue stain indicate?

Presence of iron in marrow cells Signup and view all the answers

What is the typical finding in acute leukaemia on a bone marrow smear?

Hypercellular with lymphoblasts or myeloblasts Signup and view all the answers

What role does the May-Grunwald Giemsa (MGG) stain serve?

To stain blood films for cell morphology Signup and view all the answers

What are typical red cell findings in iron deficiency anaemia?

Microcytosis, hypochromia, anisocytosis, poikilocytosis Signup and view all the answers

What is the hallmark finding in myelofibrosis?

Increased reticulin fibers Signup and view all the answers

What is the significance of hypocellular bone marrow?

Reduced blood cell production Signup and view all the answers

What does reticulin staining help assess?

Bone marrow architecture and fibrosis Signup and view all the answers

What are common findings in myelodysplastic syndrome (MDS)?

Dysplastic changes in blood cell lineages Signup and view all the answers

What is the range of normal cellularity in adult bone marrow?

30-70% Signup and view all the answers

What is the role of iron stain (Perls’ reaction) in bone marrow examination?

To assess iron stores Signup and view all the answers

Study Notes

Haemostasis

Haemostasis's primary purpose is preventing and controlling bleeding while maintaining blood fluidity.
Haemostasis mechanisms maintain blood fluidity, stop bleeding, and remove clots after healing.
These mechanisms involve blood vessels, platelets, and coagulation factors.

Clotting Trilogy

The clotting trilogy comprises blood vessels, platelets, and coagulation factors.

Primary Haemostasis

The immediate response to vessel injury, involving platelet adhesion to form a plug.
Involves von Willebrand factor (vWF) for platelet adhesion to the damaged site.
vWF is produced in Weibel-Palade bodies, alpha granules, and subendothelial connective tissue.

Secondary Haemostasis

Coagulation factors interact to create fibrin strands, strengthening the primary platelet plug.
Fibrin reinforces and stabilizes the clot.

Fibrinolysis

The process of clot breakdown following healing.
Important for preventing vascular occlusion.

Blood Vessel Wall Layers

The intima (inner layer) is composed of endothelial cells.
The media (middle layer) is composed of smooth muscle cells regulating blood pressure.
The adventitia (outer layer) provides structural support and anchors the vessel.

Anticoagulation Factors

Prostacyclin and nitric oxide inhibit platelet function and act as vasodilators.
Thrombomodulin binds thrombin, reducing clot formation.
Heparin sulfate enhances antithrombin's action on coagulation factors.
Protein C inactivates factors Va and VIIIa.
Protein S acts as a co-factor for protein C.
Tissue plasminogen promotes clot lysis.

Procoagulation Factors

Endothelial cells release endothelin-1, a vasoconstrictor.
Tissue factor (TF) initiates the coagulation cascade by binding with factor VIIa (FVIIa).
Thromboxane A2 and PAF activate platelets.

Von Willebrand Factor (vWF)

A large multimeric glycoprotein (2050 amino acids) essential for hemostasis.
Encoded by the VWF gene on chromosome 12.
vWF facilitates platelet adhesion to exposed collagen.
vWF protects factor VIII (FVIII) from degradation.
Regulated by ADAMTS13.

Vessel Injury and Haemostasis

Vessel injury exposes procoagulant material, causing vasoconstriction and platelet aggregation.
vWF activates platelets and mediates their adhesion to sites of injury.

Platelet Response

Platelets are positioned to rapidly respond to vessel damage by flowing near the vessel walls.
Platelet adhesion involves binding to exposed subendothelial matrix, vWF, or collagen.
Platelets aggregate and recruit more platelets to the injured site.
Fibrinogen mediates platelet bridge formation in the platelet plug.

Coagulation Factors

Coagulation factors are serine proteases, inactive precursors (zymogens).
Activation occurs primarily at membrane surfaces with specific binding sites.
Factors interact in a cascade, leading to fibrin formation.
Intrinsic pathway uses plasma factors.
Extrinsic pathway uses tissue factor.
Common pathway combines intrinsic and extrinsic pathways to generate fibrin.
The tissue factor-factor VIIa complex activates factor X.

Coagulation Amplification and Propagation

Thrombin activates factors V, VIII, and platelets, amplifying coagulation.
The tenase complex (FIXa + FVIIIa + FX) significantly increases thrombin production.
The prothrombinase complex (FXa + FVa + phospholipids + Ca²⁺) cleaves prothrombin to form thrombin.

Thrombin Role

Thrombin crucial for fibrinogen to fibrin conversion and clot stabilization.
Thrombin activates platelets and other factors (factors V, VII, VIII, XI, XII, protein C, and TAFI).
Thrombin promotes tissue repair.

Fibrinogen

Synthesized by hepatocytes, stored in platelets' alpha granules.
Thrombin converts soluble fibrinogen to insoluble fibrin.

FXIIIa

Stabilizes fibrin by forming cross-links, strengthening the clot to prevent degradation.
FXIIIa interacts with α2-antiplasmin to inhibit plasmin's action.

Natural Coagulation Inhibitors

Antithrombin, protein C, and TFPI inhibit coagulation.
Antithrombin inhibits thrombin and factor Xa.
Protein C, with Protein S, inactivates Factors Va and VIIIa.
TFPI blocks the tissue factor-factor VIIa complex.

Megaloblastic Anaemias

Megaloblastic anemias are characterized by delayed nuclear maturation in erythroblasts due to defective DNA synthesis.
Common causes are vitamin B12 or folate deficiencies.

Vitamin B12 (Cobalamin)

B12 is essential for DNA synthesis and is found in animal products.
Vitamin B12 is stored in the liver (3-4 years supply).
Dietary deficiency usually not problematic due to body's sufficient stores.
B12 must bind to intrinsic factor (IF) for absorption.

Vitamin B12 Absorption

B12 is bound to dietary proteins.
Salivary glands secrete R-protein.
Stomach parietal cells secrete intrinsic factor (IF).
Pepsin breaks down dietary proteins.
Free B12 binds to R-protein in the stomach.
Pancreatic proteases digest R-protein, releasing B12.
B12 binds to intrinsic factor (IF).
B12-IF complex absorbed in the terminal ileum.
B12 passes into the portal blood and binds to transcobalamin for transport.

Folate

Humans cannot synthesize folate and need dietary intake.
Folate is stored in the liver.
Absorbed as methyl-THF in the small intestine.
Converted to folate polyglutamates within cells.
Folate deficiency develops faster than B12 deficiency due to its rapid turnover.

Folate and B12 Interaction

Vitamin B12 is needed for folate metabolism by the enzyme methionine synthetase.
Methionine synthetase converts methyl-THF to THF and methylates homocysteine to methionine.
Deficiency in either vitamin affects DNA synthesis.

Clinical Features of Anemia

Fatigue, shortness of breath, pallor, jaundice, glossitis, nervous system/psychiatric disturbances are characteristic symptoms.

Lab Findings in Megaloblastic Anemia

Macrocytosis (enlarged, often oval-shaped red blood cells).
Anisocytosis (variation in red blood cell size).
Hypersegmented neutrophils (6+ lobes).
Poikilocytosis (abnormal red blood cell shapes).
Howell-Jolly bodies (nuclear remnants).
Basophilic stippling (ribosomal RNA aggregation).
Elevated serum unconjugated bilirubin and lactate dehydrogenase.

Red Cell Folate

Low red cell folate reflects folate deficiency.
Low red cell folate can occur in B12 deficiency too.

Homocysteine and Methylmalonic Acid (MMA)

Increased serum homocysteine in B12 and folate deficiencies.
Increased serum MMA only in B12 deficiency.

Investigations

Clinical assessment of anaemia → blood tests → macrocytic on blood smear → serum B12 levels → MC V, serum folate levels → LDH/unconjugated bilirubin → MMA/homocysteine.

Causes of B12 and Folate Deficiencies

B12: Lack of absorption (Congenital IF lack, Autoimmune conditions, Transcobalamin deficiency).
Folate: Poor diet, pregnancy, chronic digestive disease.

Schilling Test

A test to diagnose B12 malabsorption from dietary issues.
Uses radiolabeled B12 to measure intestinal absorption.

B12 and Folate Treatment

Treat B12 deficiencies with supplements (oral or IM).
Folate deficiency treated with increased intake of folate-rich foods or supplements.

Anemia

A condition where there are insufficient red blood cells or abnormal function.
Defined by reduced oxygen-carrying capacity of blood.
Risk factors include age, female gender, premature birth, illness, and poor diet.
Different blood parameters of haemoglobin, vary by sex and pregnancy state.

Iron: Role in Haemostasis

Iron predominantly found in erythroid bone marrow and mature erythrocytes.
Iron supplied by reticuloendothelial macrophages for new red blood cell synthesis.
Transferrin carries iron.

Iron Absorption

Iron absorbed in the duodenal epithelium.
Divalent metal transporter 1 (DMT1) facilitates iron uptake.
Haem iron absorbed via haem carrier protein 1 (HCP1) and oxygenase-aided release of iron from protoporphyrin ring.
Ferroportin transports iron.
Hephaestin oxidizes iron, assisting in transferrin binding.

Iron Storage

Stored iron mainly in liver hepatocytes as ferritin and haemosiderin.
Ferritin stores and releases iron.
Haemosiderin, aggregates of iron, proteins, and lipids, releases iron slowly.

Hepcidin

The master iron-regulating hormone produced in the liver.
A negative regulator of iron transport.
Hepcidin binds to ferroportin on cell surfaces, leading to its degradation.
Factors influencing hepcidin synthesis: infections, hypoxia, inflammation

Iron Homeostasis

Iron overload can arise from increased absorption or multiple transfusions.
Iron deficiency stems from inadequate intake, impaired absorption, or increased loss.

Iron Deficiency Anaemia (IDA)

IDA characterized by small, pale red blood cells (microcytic, hypochromic).
IDA involves variation in red blood cell size (anisocytosis), and occasional target cells or poikilocytes.

Lab Results in IDA

Serum ferritin typically low in IDA.
Serum iron typically low in IDA.
Total iron-binding capacity (TIBC) usually high in IDA.
Transferrin saturation less than 20% indicative of iron deficiency.

Perls Stain and Zinc Protoporphyrin

Perls stain detects haemosiderin stores.
Zinc protoporphyrin (ZPP) levels increase in iron deficiency.

Treatment and Management of IDA

Common oral treatment is ferrous sulfate.
Alternatives include ferrous fumarate or ferrous gluconate.
Therapy typically for 3 months.
Parenteral iron for non-responsive cases.
Response indicators: reticulocyte and hemoglobin improvement along with iron replenishment (6 months).

Lab Investigation of Coagulation

Evaluate platelet function through assays and coagulation cascade through prothrombin time (PT), APTT, fibrinogen levels, thrombin time, and D-dimers.

Sample Collection and Coagulation Analysers

Sodium citrate prevents coagulation by removing calcium ions.
Samples centrifuged at high speed (3500 rpm for 5 minutes) to yield platelet-poor plasma (PPP).
Coagulation analysers employ optical or mechanical principles to measure clotting times.

Platelet Function Assays

Used to investigate platelet adhesion and aggregation.
ADP and EPI used in assays to stimulate platelet function.
Samples kept at room temperature, delivered by hand, processed within 4 hours.

Platelet Dysfunction

Platelet function assay results vary depending on the specific platelet disorder (e.g., vWD types).

Prothrombin Time (PT)

PT assesses the extrinsic and common pathways of coagulation.
Assesses Factor II, V, VII, and X.

INR (International Normalized Ratio)

INR derived from PT to monitor anticoagulant therapy (e.g., warfarin).

APTT (Activated Partial Thromboplastin Time)

APTT assesses intrinsic and common pathways of coagulation.
APTT particularly sensitive to factors VIII, IX, and XI deficiencies.

Clotting Screen Interpretation

Prolonged PT and APTT indicate common pathway issues.
Prolonged APTT, normal PT suggests intrinsic pathway issue.

Clauss Fibrinogen Test

Used to measure fibrinogen levels in plasma.
Uses thrombin to initiate fibrin formation.

Fibrinogen Testing

Measures fibrinogen using plasma dilutions.

Thrombin Time (TT)

TT measures fibrinogen conversion to fibrin.

Bleeding Disorders: Symptoms, Mechanisms, and Example Conditions

Symptoms include epistaxis, bruising, purpura, petechiae, menorrhagia, joint/muscle bleeds, and anaemia.
Primary haemostatic defects feature small bruises and easy bleeding from cuts.
Acquired bleeding disorders: Vitamin K deficiency, liver disease, DIC, and autoantibodies/inhibitors.

Vitamin K Deficiency

A fat-soluble vitamin found in green leafy vegetables and liver.
Causes: Fat malabsorption, liver disease, oral anticoagulants, antibiotics.
Crucial cofactor for gamma-carboxylation of clotting factors.
Deficiency leads to prolonged PT and APTT.

Vitamin K Cycle

Gamma-carboxylation is crucial for vitamin K-dependent proteins.
Calcium chelation enables binding to phospholipids.

Coagulation Cascade and Vitamin K

Crucial vitamin in activating Factors II, VII, IX X.
Activated factors require vitamin K.

Liver Disease and Coagulation

Liver produces factors I (Fibrinogen), II, V, VII, IX, X and part of VIII.
Liver disease impairs factor production, leading to prolonged PT and APTT, decreased platelet count.

Massive Haemorrhage

Significant blood loss (>50% circulating volume in 3 hours).
Consumptive coagulation due to depletion of clotting factors and platelets.

Platelet Transfusions

Indications include thrombocytopenia, platelet dysfunction.

Plasma Products

Fresh Frozen Plasma (FFP), Cryoprecipitate, Octaplas (SD-FFP) used in coagulation replacement therapy.

Disseminated Intravascular Coagulation (DIC)

Inappropriate intravascular fibrin deposition consumes clotting factors and platelets, leading to bleeding and organ damage.
Treatment focuses on the underlying cause and replacement therapy.

Autoantibodies/Inhibitors in Coagulation

Antibodies targeting clotting proteins, often found with autoimmune conditions.
Common targets include factors VIII and IX.
Antiphospholipid antibodies affect multiple coagulation proteins.

Haemophilia A and B

Both are X-linked bleeding disorders, representing deficiency in clotting Factor VIII (Haemophilia A) and IX (Haemophilia B) respectively.
Haemophilia inherited through the X chromosome.
Severity ranges from mild to severe cases in terms of Factor presence.

Haemophilia Treatment

Prophylaxis with plasma-derived or recombinant clotting factors.
Desmopressin (DDAVP) can increase factor VIII levels (in some mild cases)

von Willebrand Disease (vWD)

vWD is an inherited bleeding disorder with varying severity.
vWD caused by quantitative or qualitative deficiency of von Willebrand factor (vWF).
vWD classified into types 1, 2, and 3.

Platelet Disorders

Characterized by abnormal or excessive bleeding due to platelet abnormalities.
Quantitative defects (thrombocytopenia) or qualitative defects (platelet dysfunction).

Haemopoiesis

Haemopoiesis: Formation of blood cells in the bone marrow.
Adult haemopoiesis primarily in axial skeleton bone marrow.
HSCs (Haematopoietic Stem Cells).
Differentiation pathways: Myeloid (RBCs, platelets, myeloid WBCs) and Lymphoid (lymphocytes).
Stages of erythropoiesis, thrombopoiesis, granulopoiesis, monocytopoiesis, and lymphopoiesis.
Haemopoietic growth factors regulate these processes.

Haemopoiesis Regulation

Bone marrow microenvironment and cells (stromal, matrix) are crucial.
Regulation includes cytokines, EPO, TPO, adhesion molecules, and transcription factors like HIF.
Extra-medullary production possible due to bone marrow failure or high need.

Haemopoietic Disorders

Aplastic anemia, MDS, Polycythemia vera, Leukaemias.
Treatments range from EPO injections, TPO agonists, GCSF, Bone marrow transplant.

Cell Production Rates

High cell production rates of Red Blood cells (RBCs), White Blood cells (WBCs), and platelets in normal haematopoiesis.

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This quiz covers the essential mechanisms of haemostasis, including primary and secondary haemostasis. Learn about the roles of blood vessels, platelets, coagulation factors, and the process of fibrinolysis in preventing and controlling bleeding. Test your knowledge on how these components work together to maintain blood fluidity and promote healing.

Haemostasis and Clotting Mechanisms

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Questions and Answers

What is the main purpose of haemostasis?

Which elements form the clotting trilogy?

What is primary haemostasis?

What role does fibrin play in secondary haemostasis?

What is fibrinolysis?

Which layer of the blood vessel wall is responsible for regulating vascular tone?

What is the primary function of the adventitia layer in blood vessels?

What is the role of the intima in blood vessels?

What initiates the extrinsic pathway of the coagulation cascade?

What is the primary role of the TF-FVIIa complex in coagulation?

What does factor Xa do in the context of the extrinsic pathway?

Which component is NOT part of the extrinsic prothrombinase complex?

What is the function of calcium ions (Ca²⁺) in the coagulation cascade?

What role does factor Va (FVa) serve in the coagulation process?

Which of the following is a natural inhibitor of the coagulation process?

How does protein C act as an inhibitor in coagulation?

What is the main storage location of vitamin B12 in the body?

What characterizes megaloblastic anemia?

What is a major cause of megaloblastic anemia?

What occurs during the amplification stage of coagulation?

What is the main role of thrombin in the coagulation process?

What is the primary source of vitamin B12 for animals?

How is a factor assay result interpreted?

Which type of inhibitors are known to lose activity over time?

What is a Bethesda Unit (BU) used to measure?

What is the purpose of the Ristocetin Cofactor assay?

What symptoms are commonly associated with bleeding disorders?

In which scenario does a deficiency of a specific factor manifest during a factor assay?

Which of the following factors are vitamin K-dependent?

What is the role of gamma-carboxylation in the vitamin K cycle?

What is a common cause of vitamin K deficiency?

Which conditions are classified as acquired bleeding disorders?

How does vitamin K deficiency affect clotting times?

What type of assay is used to detect Factor VIII inhibitors?

What happens to vitamin K-dependent factors in the body during vitamin K deficiency?

What are the three main components of haemostatic mechanisms?

What is the primary role of von Willebrand factor (vWF) in haemostasis?

How is the platelet plug primarily formed?

What initiates the process of secondary haemostasis?

Which statement best describes thromboxane A2's role in procoagulation?

Where is von Willebrand factor (vWF) primarily produced?

What benign role does protein C serve in anticoagulation?

How is fibrinolysis inhibited during the procoagulation process?

What is the role of tissue factor in the coagulation process?

Which factor is crucial for the localized activation of coagulation factors?

What is the structure of von Willebrand factor (vWF)?

How does protein S function in the anticoagulation pathway?

Why is it important for the coagulation factor activation to occur at membrane surfaces?

What is indicated by increased levels of serum methylmalonic acid (MMA)?

What do normal levels of both methylmalonic acid and homocysteine suggest?

What is the gold standard test for determining the cause of B12 deficiency?

What is the first step in the Schilling test?

Which of these is a main cause of B12 deficiency?

Why is folic acid often administered with B12 treatment?

What is a possible consequence of pancreatic enzyme insufficiency?

Which condition is NOT associated with folate deficiency?

What does a blood test showing macrocytic cells typically indicate?

What is the primary role of reticuloendothelial macrophages in relation to iron?

Which of the following is NOT a mechanism by which anemia can occur?

What is a common factor in cases of folate deficiency?

What is the primary function of transferrin in the body?

Which vitamin is primarily associated with the absorption issues identified in the Schilling test?

What dietary inclusions are recommended for increasing B12 intake?

Where is the majority of stored iron primarily found in the body?

What is the primary mechanism by which dietary iron is absorbed in mammals?

How is ferric iron (Fe³⁺) converted to ferrous iron (Fe²⁺) for absorption?

Which of the following statements regarding hepcidin is accurate?

What effect does a transferrin saturation of less than 20% indicate?

What factors are assessed in an extrinsic pathway factor assay?

Which factor does NOT influence hepcidin synthesis?

What does it suggest if both PT and APTT are prolonged?

What are the characteristic features observed in a blood film of an individual with iron deficiency anemia?

How is the total iron-binding capacity (TIBC) measured?

What is the primary diagnostic application of a D-dimer test?

What condition can lead to a prolonged APTT?

What is the standard oral treatment regimen for iron deficiency anemia (IDA)?