Hematology Quiz: Blood Cell Indices

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Questions and Answers

What does high RDW indicate about red blood cells?

High variability in RBC sizes (correct)

Normal variation in RBC shapes

Increased number of large RBCs

Pale RBCs due to low hemoglobin

Which term describes marked variation in the shape of RBCs?

Macrocytosis

Anisocytosis

Poikilocytosis (correct)

Hypochromia

What does reticulocytosis indicate?

Decreased RBC production

Normal response to blood loss or anemia (correct)

Normal bone marrow response

Increased destruction of RBCs

Which condition is characterized by increased destruction of RBCs?

Hemolytic anemia Signup and view all the answers

What is indicated by a low reticulocyte count in the presence of anemia?

Malfunctioning marrow due to nutrient deficiency Signup and view all the answers

What is a visual counterpart of decreased MCHC?

Hypochromia or hypochromasia Signup and view all the answers

Which of the following conditions is a possible cause of leukopenia?

Autoimmune conditions Signup and view all the answers

According to the World Health Organization, anemia is defined as Hb levels below what value?

< 130 g/L Signup and view all the answers

What might an increased Mean Platelet Volume (MPV) indicate in an individual with thrombocytopenia?

Normal bone marrow response Signup and view all the answers

What is indicated if both reticulocyte count and platelet count are normal or low in a patient with anemia?

Secondary anemia due to chronic disease Signup and view all the answers

Which of the following is a normal range for red blood cell (RBC) count in adult males?

4.7 to 6.1 million cells/mL Signup and view all the answers

Which of the following conditions is associated with leukocytosis?

Bacterial infection Signup and view all the answers

What does a hematocrit (Hct) value measure?

Proportion of RBCs to total blood volume Signup and view all the answers

Which option describes a potential cause of thrombocytopenia?

Sepsis Signup and view all the answers

What is one possible cause of thrombocytosis?

Spleen removal (splenectomy) Signup and view all the answers

What normal range does hemoglobin concentration (Hb) typically fall into for adult males?

13.0-18.0 g/dL Signup and view all the answers

What is included in a complete blood count (CBC)?

Red blood cell count Signup and view all the answers

What is the normal range of white blood cells (WBCs) in a person's blood?

4,500 - 11,000 WBC/mL Signup and view all the answers

Which type of white blood cells should typically make up 40-75% of the total WBC count?

Neutrophils Signup and view all the answers

Which parameter in a complete blood count indicates the volume of red blood cells?

Hematocrit (Hct) Signup and view all the answers

What is the typical percentage range for lymphocytes in a white blood cell differential?

20-45% Signup and view all the answers

What does a low Mean Corpuscular Volume (MCV) indicate about red blood cells?

The RBCs are smaller than normal. Signup and view all the answers

Which condition is associated with an MCHC value below 32 g/dL?

Iron deficiency anemia Signup and view all the answers

What is the normal range for Mean Corpuscular Hemoglobin (MCH)?

27-31 pg Signup and view all the answers

What does Red Cell Distribution Width (RDW) measure?

The variation in the size of RBCs. Signup and view all the answers

If a patient has macrocytic anemia, which of the following is likely true about their MCH level?

MCH is elevated. Signup and view all the answers

Which of the following conditions is associated with a high MCHC?

Hereditary spherocytosis Signup and view all the answers

What does an MCV greater than 97 fl suggest about red blood cells?

The RBCs are larger than normal. Signup and view all the answers

What normal RDW-CV range indicates a healthy distribution of red blood cell sizes?

11.5-14.5% Signup and view all the answers

Study Notes

Clinical Chemistry Case Study

Included conditions: megaloblastic anemia, hemolytic anemias, G6PD deficiency anemia, iron deficiency anemia, and beta thalassemia.

Complete Blood Count (CBC)

A common blood test
Calculates cells and cell fragments in plasma
Determined by machines analyzing blood components.
Measures white blood cells, red blood cells, and platelets.
Ordered when clinical findings indicate blood cell disorders (e.g., infection, inflammation, malignancies, bruising, or bleeding).

Parameters of CBC

White blood cell count (WBC or leukocyte count)
WBC differential count
Red blood cell count (RBC or erythrocyte count)
Hematocrit (Hct)
Hemoglobin (Hb)
Mean corpuscular volume (MCV)
Mean corpuscular hemoglobin (MCH)
Mean corpuscular hemoglobin concentration (MCHC)
Red cell distribution width (RDW)
Platelet count
Mean Platelet Volume (MPV)

White Blood Cell (WBC) Count and Differential

WBC count: Total number of white blood cells in a blood sample.
Normal range: 4,500-11,000 WBC/mL.
WBC differential: Identifies and counts various white blood cell types.
Types of WBCs: neutrophils, lymphocytes, eosinophils, monocytes, and basophils.
Percentage ranges for each WBC type are included.

Leukopenia and Leukocytosis

Leukopenia: Low WBC count, caused by bone marrow disorders, autoimmune conditions, severe infections, cancers, and immune system diseases (e.g., HIV).
Leukocytosis: High WBC count, caused by infections (especially bacterial), inflammation, leukemia, myeloproliferative disorders, allergies, tissue death, and intense exercise.

Platelet Count (RBCs)

Normal range: 150,000-450,000 platelets per microliter of blood.
Thrombocytosis possible causes: reactive to acute trauma, surgery, blood loss, iron deficiency, chronic infections, inflammatory diseases, rheumatoid arthritis, ulcerative colitis, or splenectomy.
Thrombocytopenia possible causes: spurious lab result, immune-mediated, medications, viral infection, leukemia, sepsis, or hypersplenism.

Mean Platelet Volume (MPV)

"Young" platelets are typically slightly larger.
Increased MPV indicates normal bone marrow response.
Decreased or low normal MPV may indicate impaired bone marrow response.

Erythrocyte Count (RBCs)

Counts the actual number of red blood cells in a blood sample.
Normal range: Male: 4.7 to 6.1 million cells/µL; Female: 4.2 to 5.4 million cells/µL.

Hemoglobin Concentration and Hematocrit (Hct)

Hemoglobin Concentration (Hb): Amount of hemoglobin in whole blood (grams per deciliter).
Normal values (Hb): Adult males: 13.0-18.0 g/dL; Adult, non-pregnant females: 11.5-16.5 g/dL.
Hematocrit (Hct): Volume of RBCs compared to the total blood volume (RBCs + plasma); also called packed cell volume (PCV).
Normal values (Hct): Adult males: 42-52%; Adult females: 37-47%.

Red Blood Cell Indices

Calculations providing information on RBC physical characteristics.
Mean corpuscular volume (MCV): Average size of RBCs (Normal: 80-97 fl).
Mean corpuscular hemoglobin (MCH): Average amount of hemoglobin inside an RBC (Normal: 27-31 pg).
Mean corpuscular hemoglobin concentration (MCHC): Average percentage of hemoglobin inside an RBC (Normal: 32-36 g/dL).
Red cell distribution width (RDW): Variation in the size of RBCs.

Mean Corpuscular Volume (MCV)

Indicates the average volume of red blood cells (Normal: 80-97 fl).
MCV < 80 fl: Smaller than normal RBCs (microcytic); caused by iron deficiency anemia or thalassemia.
MCV > 97 fl: Larger than normal RBCs (macrocytic); caused by vitamin B12 or folate deficiency.
Normal MCV: Normocytic RBCs.

Mean Corpuscular Hemoglobin Concentration (MCHC)

Indicates the average concentration of hemoglobin in a single RBC. (Normal: 32-36 g/dL).
MCHC < 32 g/dL: Hypochromic; caused by iron deficiency anemia and thalassemia.
MCHC > 36 g/dL: Hyperchromic; caused by hereditary or acquired RBC membrane disorders.

Mean Corpuscular Hemoglobin (MCH)

Average quantity (mass) of hemoglobin in red blood cells (Normal: 27-31 pg).
Low MCH: Microcytic anemia, normocytic hypochromic RBCs.
High MCH: Macrocytic anemia, spherocytosis (with hyperchromia).

Red Cell Distribution Width (RDW)

Measures variability in the size of red blood cells.
Normal range: RDW-CV: 11.5-14.5%; RDW-SD: 40.0-55.0 fL.
High RDW: High variability in RBC sizes.
Anisocytosis and poikilocytosis are seen in peripheral blood smears.

Descriptive Terms Used on Peripheral Smears

Anisocytosis: Marked variation in RBC sizes.
Poikilocytosis: Variations in RBC shape.
Hypochromia: RBCs appear paler than normal due to low hemoglobin.
Macrocytosis: Increased number of large RBCs.
Microcytosis: Increased number of small RBCs.

Reticulocyte Count

"Young" red blood cells recently released from the bone marrow.
Normal range: 0.5-2.5% of total red blood cells.
Elevated reticulocyte count: Indication of bone marrow response to blood loss.

Anemia

Reduction in one or more major RBC measurements (Hb, Hct, RBC count), related to RBC mass and plasma volume.
WHO criteria: Hb < 130 g/L (<13 g/dL) or Hct < 39% in adult males; Hb < 120 g/L (<12 g/dL) or Hct < 37% in adult non-pregnant females.

Anemia: History

Bleeding history (NSAIDS, ASA).
Menstrual history.
Past medical history of anemia or similar symptoms.
Alcohol, nutritional questions.
Chronic diseases, renal diseases, environmental/work toxins (e.g., lead).

Symptoms of Anemia

Dependent on the degree and rate of anemia, oxygen demand.
Hypovolemia occurs in acute blood loss: Symptoms include exertional dyspnea, fatigue, palpitations, bounding pulses, headache, presyncope, dizziness, worsening CHF or angina pectoris, pica (cravings for non-nutritional substances), and pagophagia (eating ice).

Signs of Anemia

Tachycardia
Pallor
Jaundice (related to cause)
Koilonychia ("spoon nails")
Splenomegaly, lymphadenopathy
Petechiae, ecchymoses
Atrophy of tongue papillae

Classification of Anemias

Classified according to pathophysiological mechanism (decreased RBC production, increased RBC destruction, blood loss).
Classified according to RBC size (macrocytic, normocytic, microcytic).

Common Causes of Anemia (Based on RBC Morphology)

Diagram showing classifications of anemia by MCV (<80, 80-100, >100) and related investigations (Serum iron studies, Reticulocyte count, Megalocytes).

Macrocytic Anemias

Macrocytosis: Increased MCV (above normal range).
Megaloblastic and Non-Megaloblastic types (dependent on bone marrow findings).
Investigation usually involves serum B12 and red cell folate measurement.

Megaloblastic Anemia

Group of disorders characterized by distinctive morphologic appearances of developing red blood cells (megaloblasts).
Defective DNA synthesis is the underlying mechanism.
May affect WBCs (hypersegmented neutrophils) and platelets (thrombocytopenia).

Causes of Megaloblastic Anemia

Deficiency of cobalamin (vitamin B12) or folate.
Genetic or acquired abnormalities affecting vitamin metabolism.
Defects in DNA synthesis unrelated to cobalamin or folate.
Diagnosis includes clinical findings, CBC/blood morphology, and measuring folate and vitamin B12 levels.

Peripheral Findings in Megaloblastic Anemia

Oval-shaped macrocytes, often with anisocytosis and poikilocytosis
Hypersegmented neutrophils (more than five nuclear lobes) possible leukopenia or moderate thrombocytopenia
Ineffective hematopoiesis that leads to unconjugated hyperbilirubinemia and raised serum lactate dehydrogenase.
CBC findings: Decreased hemoglobin and hematocrit, increased MCV, increased MCH, and normal MCHC.

Hemolytic Anemia

Anemia resulting from increased destruction of red blood cells (life span <100 days).
Compensatory increase in erythropoietin secretion, leading to reticulocytosis.
Clinical features: jaundice, splenomegaly, pigmented gallstones.
Possible causes: intrinsic to RBCs (e.g., abnormalities in hemoglobin, red blood cell membrane, or metabolic factors needed to generate ATP), or extrinsic to RBCs (e.g., acquired disorders, auto-immune or transfusion reactions, damage in spleen, trauma, and exposure to compounds with oxidant potential).
Lab investigations: Low Hb, Elevated LDH, elevated indirect bilirubin, decreased haptoglobin, abnormally shaped RBCs, and elevated reticulocyte count. Intravascular vs. Extravascular location.

Causes of Hemolysis (Intrinsic to RBCs)

Abnormalities in hemoglobin (e.g., thalassemia).
Defects in red blood cell membrane (e.g., spherocytosis).
Abnormalities in reducing power (e.g., G6PD deficiency).

Causes of Hemolysis (Extrinsic to RBCs)

Acquired disorders (e.g., autoimmune hemolytic anemia, transfusion reaction).
Damage in the spleen; hypersplenism.
Trauma
Prosthetic heart valve
Exposure to compounds with oxidant potential
Sulfonamides in those with G6PD
Destruction of RBC by pathogens (e.g., malaria).

Site of Hemolysis

Intravascular hemolysis: Immediate lysis in circulation, releasing hemoglobin into plasma. (Free Hgb binds to haptoglobin, complex taken up by liver) Hemoglobinuria.
Extravascular hemolysis: Cell destruction via monocyte-macrophage system in liver, spleen, or bone marrow.

Lab Investigations (for Hemolytic Anemia)

Low hemoglobin, elevated LDH & indirect bilirubin
Decreased haptoglobin
Abnormally shaped RBCs
Elevated reticulocyte count (RBCs are usually in the circulation for normal life span of about 120 days.)
Reticulocyte Index: Increased

Clinical Biochemistry Case Study (G6PD Deficiency & Oxidative Hemolytic Anemia)

Case history details: Patient information, chief complaint (black urine, fever, headache), past medical history (multiple sclerosis), recent exposure.
Details of treatment: Steroids, high-dose vitamins, and minerals.
Social / Family history.
Lab Results: Low Hb, increased reticulocyte count, elevated WBC, positive G6PD deficiency screen, bite cells on blood film, G6PD assay low.
Further tests and management: G6PD assay (quantitatively low; normal range 5.34-11.34), Blood transfusion, intravenous fluids, folic acid, and iron supplementation; current medications stopped.
Follow-up: Hemoglobin stabilizes, hemoglobinuria improves, no further hemolytic episodes, family screened.

Glucose-6-phosphate Dehydrogenase (G6PD) Deficiency

X-linked recessive inherited disease, higher prevalence in males.
Characterized by hemolytic anemia due to inability to detoxify oxidizing agents.
The most common disease-producing enzyme abnormality in humans.
Caused by mutations in the G6PD gene.
Clinical presentation variable: asymptomatic, hemolysis, neonatal jaundice.
High-dose vitamin C may cause G6PD deficiency.
WHO classification of G6PD deficiency into five classes based on G6PD activity levels.
Diagnostic methods include clinical findings, CBC, blood morphology, differential tests (e.g., Beutler test, quantitative assay of GPD activity), and looking for bite cells or Heinz bodies. G6PD assay.

Iron Metabolism

Iron is a critical component of hemoglobin.
Iron is absorbed in the duodenum and upper jejunum as ferrous (Fe2+) form.
Absorption is improved by reducing substances.
Transferrin is the most dynamic carrier, and serum total iron-binding capacity (TIBC) is a measure of its binding capacity, usually elevated in iron deficiency and low in iron overload, liver disease, infection, malignancy, and protein deficiency.
Ferritin is an intracellular protein that stores iron and releases it as needed; serum ferritin is used as a diagnostic test for iron deficiency anemia.

Iron Deficiency Anemia

Common cause of anemia worldwide.
Iron is needed by the body, but when the required amount exceeds the readily available iron, iron stores are depleted.
Red blood cell formation is abnormal, resulting in anemia.
Causes include chronic blood loss (e.g., from the uterus or gastrointestinal tract), increased demands (e.g., during growth or pregnancy), or decreased absorption.
Investigations include blood film (microcytic, hypochromic, anisocytosis, poikilocytosis), and CBC. Serum ferritin and TIBC are also measured. A trial of iron supplementation is sometimes used for diagnosis.

Hemoglobin Disorders

Hemoglobinopathy: Inherited mutation (qualitative), abnormal globin synthesis
Thalassemia: Inherited mutations (quantitative), abnormal globin synthesis.

Thalassemia

Inherited disorders of a- or β-globin biosynthesis.
Defect in globin chain synthesis. Reduced supply of globin diminishes hemoglobin tetramer production, leading to hypochromia and marked microcytosis and decreased MCHC.
Variants cause a range in severity.
Diagnosis includes blood film (microcytosis, hypochromia, target cells, etc.) and hemoglobin electrophoresis.

Sickle Cell Anemia

A genetic disorder characterized by hemolytic anemia and vasculopathy.
Mutation in the ẞ-globin chain of hemoglobin, where glutamic acid is replaced by valine.
Individuals have abnormal hemoglobin-S, causing RBC sickling and hemolysis.
Constant RBC destruction by the spleen. Frequent occurrences of microvascular disruption, and risk of infection.

Sickle Cell Trait

βs/βa genotype (carriers). Asymptomatic but may have partial protection against malaria.
Sickling may occur under specific conditions (e.g., high altitude).

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Test your knowledge on key concepts in hematology, including red blood cell indices, reticulocytosis, and conditions like anemia and thrombocytopenia. This quiz covers definitions, causes, and normal ranges related to blood cell counts and conditions affecting blood health.