Red Blood Cell Biology and Function
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Questions and Answers

Which of the following protein combinations is primarily responsible for maintaining the structural integrity of the red blood cell (RBC) membrane?

  • Zeta, Epsilon, and Beta globin
  • Hemoglobin and 2,3-DPG
  • Glycophorin and Band 3 protein
  • Spectrin, Ankyrin, Actin, and Protein 4.1 (correct)

During fetal development, the activation of globin genes progresses exclusively from Zeta to Alpha to Beta.

False (B)

What two key functions does the Band 3 protein perform in red blood cells?

Anion transport and cytoskeleton anchoring

Rigid red blood cells are often removed from circulation by the ______, leading to reduced RBC survival.

<p>spleen</p> Signup and view all the answers

Which of the following metabolic processes is essential for providing energy to maintain erythrocyte function?

<p>Glycolysis (A)</p> Signup and view all the answers

In the hemoglobin-oxygen dissociation curve, what does a right shift indicate?

<p>Decreased oxygen affinity (A)</p> Signup and view all the answers

When hemoglobin binds oxygen, it transitions to the tense (T) state, which increases its affinity for oxygen.

<p>False (B)</p> Signup and view all the answers

Match the condition with its corresponding shift on the hemoglobin-oxygen dissociation curve:

<p>Anemia = Right shift Multiple transfusions of stored blood = Left shift Acidosis = Right shift Hypothermia = Left shift</p> Signup and view all the answers

A unit of blood stored with CPDA-1 can be stored for how long?

<p>35 days (C)</p> Signup and view all the answers

During blood storage, the pH level increases.

<p>False (B)</p> Signup and view all the answers

What cryoprotective agent is added to RBCs before freezing?

<p>Glycerol</p> Signup and view all the answers

The addition of adenine to blood storage solutions increases levels, thereby driving glycolysis toward ATP synthesis.

<p>ADP</p> Signup and view all the answers

Match the following blood preservatives with their corresponding storage duration:

<p>ACD = 21 days CPD/CP2D = 21 days CPDA = 35 days</p> Signup and view all the answers

Which of the following is a consequence of low 2,3-DPG levels in stored blood?

<p>Left shift in the oxygen dissociation curve (B)</p> Signup and view all the answers

What is a key benefit of using additive solutions in RBC storage?

<p>Extending the shelf-life of RBCs to 42 days (D)</p> Signup and view all the answers

PVC plastic bags are ideal for storing blood components during freezing due to their durability at low temperatures.

<p>False (B)</p> Signup and view all the answers

Why is glycerol used in the process of freezing RBCs?

<p>To protect the cells from damage caused by ice crystal formation. (A)</p> Signup and view all the answers

RBCs frozen with glycerol can be stored indefinitely without any degradation.

<p>False (B)</p> Signup and view all the answers

What is the minimum storage temperature (in Celsius) generally required for RBCs preserved with glycerol?

<p>-65</p> Signup and view all the answers

The process of removing glycerol from RBCs after thawing is known as ____________.

<p>deglycerolization</p> Signup and view all the answers

Match the advantages and disadvantages of using frozen RBCs:

<p>Long-term storage (10 years) = Advantage Maintenance of RBC viability and function = Advantage Storage requirements (--65°C) = Disadvantage A time-consuming process = Disadvantage</p> Signup and view all the answers

What is the primary consequence of decreased levels of 2,3-DPG in stored RBCs?

<p>Increased hemoglobin affinity for oxygen (D)</p> Signup and view all the answers

How does the body compensate for decreased oxygen release to tissues due to low 2,3-DPG levels in stored RBCs?

<p>By increasing cardiac output (C)</p> Signup and view all the answers

Which of the following is a direct result of reduced oxygen unloading in tissues that experience hypoxia?

<p>Decreased mixed venous oxygen tension ($PvO_2$) (D)</p> Signup and view all the answers

What effect does 2,3-DPG have on hemoglobin's affinity for oxygen?

<p>Lowers hemoglobin's affinity for oxygen, facilitating oxygen release in tissues. (B)</p> Signup and view all the answers

Reverse grouping (serum typing) involves testing a patient's red blood cells with known antisera.

<p>False (B)</p> Signup and view all the answers

Why is 0.85% saline the preferred solution for washing red blood cells?

<p>It is isotonic to red blood cells</p> Signup and view all the answers

In the context of blood banking, a purple top tube contains ______ whole blood.

<p>EDTA</p> Signup and view all the answers

What is the primary purpose of Coombs Check Cells (CCC)?

<p>To validate a negative AHG test. (A)</p> Signup and view all the answers

A 2+ reaction observed after centrifuging AHG with Coombs Check Cells indicates an undersensitized or oversensitized cell issue.

<p>False (B)</p> Signup and view all the answers

In ABO blood typing, what component is used for forward grouping (cell typing)?

<p>Patient's red blood cells and known antisera. (D)</p> Signup and view all the answers

To prepare 100 mL of a 10% bleach solution, mix 10 mL of bleach with ______ mL of diluent.

<p>90</p> Signup and view all the answers

Which potentiator works by decreasing the ionic strength of the solution?

<p>LISS (Low Ionic Strength Solution) (D)</p> Signup and view all the answers

PEG enhances agglutination by decreasing the viscosity of the solution.

<p>False (B)</p> Signup and view all the answers

What is the primary function of albumin as a potentiator in agglutination reactions?

<p>protein stabilizer</p> Signup and view all the answers

______ enhances agglutination reactions by increasing the rate of molecular interactions due to higher kinetic energy at warmer temperatures.

<p>Phosphate-buffered saline</p> Signup and view all the answers

Match the potentiator with its mechanism of action:

<p>LISS = Reduces ionic strength Albumin = Protein stabilizer PEG = Increases viscosity Warm Saline = Increases kinetic energy</p> Signup and view all the answers

IgG is an incomplete antibody, What test phase might it be detected in?

<p>Antihuman globulin (AHG) phase (C)</p> Signup and view all the answers

Monoclonal antibodies target multiple different antigens.

<p>False (B)</p> Signup and view all the answers

Name two blood group systems that typically exhibit weaker reaction strengths.

<p>Kidd and Duffy</p> Signup and view all the answers

Why is it important to invert the tube before taking cells for a cell compatibility check (CCC)?

<p>To ensure the sample is not too postzone due to taking cells from the packed cell portion. (C)</p> Signup and view all the answers

In the U.S., platelet storage is limited to 10 days due to the risk of bacterial contamination.

<p>False (B)</p> Signup and view all the answers

List three changes that occur to platelets during platelet storage lesion.

<p>Decreased ATP, decreased pH, increased degranulation</p> Signup and view all the answers

During platelet storage lesion, platelet morphology changes from discoid to _______ shapes.

<p>spherical</p> Signup and view all the answers

Which of the following best explains why a sample that is under-centrifuged would result in a false negative?

<p>The cells will be packed loosely and will not agglutinate. (A)</p> Signup and view all the answers

Which of the following is the most likely cause of rouleaux formation?

<p>Increased protein in circulation. (C)</p> Signup and view all the answers

Match the agglutination grading with its description:

<p>4+ = One solid agglutinate 3+ = Medium to large agglutinates 2+ = Small to medium agglutinates with a clear background 1+ = Small agglutinates with a turbulent background</p> Signup and view all the answers

A patient with blood type A receives a transfusion of type O red blood cells. What result would you expect to see upon immediate post-transfusion testing, when testing for A antigen?

<p>Mixed field agglutination (C)</p> Signup and view all the answers

Flashcards

Integral membrane proteins

Proteins embedded in the cell membrane contributing to RBC structure.

Peripheral proteins

Proteins attached to the outer or inner membrane surface of RBCs.

Band 3 protein

A multifunctional protein crucial for anion transport and cytoskeleton anchoring in RBCs.

Deformability

The ability of RBCs to change shape as they pass through narrow capillaries.

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RBC metabolism

Biochemical processes in red blood cells necessary for energy production.

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Hemoglobin-Oxygen Dissociation Curve

Graph showing the relationship between oxygen pressure and hemoglobin saturation.

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Right shift conditions

Factors that decrease hemoglobin's affinity for oxygen, enhancing O2 release.

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Left shift conditions

Factors that increase hemoglobin's affinity for oxygen, making it hold onto O2 more tightly.

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2,3-DPG Levels

Stored blood has low 2,3-DPG, affecting oxygen release from hemoglobin.

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Oxygen Dissociation Curve Shift

A left shift occurs with low 2,3-DPG, increasing hemoglobin's oxygen affinity.

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Factors Decreasing in Stored RBCs

Viable cells, glucose, ATP, and pH decrease in stored blood.

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Factors Increasing in Stored RBCs

Lactic acid and potassium (K+) levels increase in stored blood.

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Adenine in CPDA-1

Adenine helps maintain ATP by driving glycolysis in preserved blood.

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Storage Duration of CPDA

CPDA-1 allows blood storage for 35 days.

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Material for RBC Storage

Plastic material must be permeable to CO2 to maintain pH during storage.

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Cryoprotective Agent

Glycerol is added to RBCs for freezing, required in cells under 6 days old.

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Agglutination Grading

A system to classify the size and density of agglutinates in blood tests.

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Platelet Lifespan

Platelets have a typical lifespan of 8 to 10 days in circulation.

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Storage Limit for Platelets

Platelets can only be stored for 5 days due to contamination risks.

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Platelet Storage Lesion

Changes occurring in platelets during storage, including morphology and pH changes.

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Corrected Count Increment (CCI)

A measure to evaluate how much platelet levels rise after a transfusion.

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False Negatives/Positives in Centrifugation

Results that are inaccurately low or high due to improper centrifuge techniques.

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Mix Field Agglutination

Occurs after a transfusion when different blood types react in tests.

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Rouleaux Formation

A stack-like arrangement of red blood cells due to increased protein levels.

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Glycerol in RBC freezing

Glycerol protects RBCs during freezing by penetrating their cells.

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-65°C storage requirement

RBCs need to be stored below -65°C for effective preservation.

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Advantages of RBC freezing

Long-term storage (10 years), maintains RBC viability.

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Disadvantages of RBC freezing

Time-consuming, expensive, and strict storage needs.

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Impact of low 2,3-DPG

Low levels increase cardiac output but decrease oxygen release to tissues.

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Increased cardiac output

Body compensates for hypoxia by boosting heart rate and stroke volume.

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Decreased mixed venous oxygen tension

Less oxygen released to tissues leads to reduced oxygen content in venous blood.

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Role of IgG in RBC sensitization

IgG helps with sensitization but needs other factors for lattice formation.

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2,3-DPG

A molecule that lowers hemoglobin's affinity for oxygen, facilitating oxygen release in tissues.

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ABO Blood Typing

A method to determine an individual's blood type based on the presence of A and B antigens.

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Forward Grouping

A blood typing procedure where red blood cells are mixed with antisera to identify blood type.

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Reverse Grouping

A blood typing method that checks serum against known A and B cells to confirm blood type.

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0.85% Saline Solution

An isotonic solution used for washing red blood cells to prevent swelling or shrinking.

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Coombs Check Cells (CCC)

Cells used to validate a negative Antihuman Globulin (AHG) test for antibodies on red blood cells.

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Direct Antiglobulin Test (DAT)

Tests for antibodies already bound to red blood cells in a patient’s sample.

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Indirect Antiglobulin Test (IAT)

Tests for free antibodies in serum that could react against donor red blood cells.

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Potentiators

Substances that enhance agglutination reactions in blood testing.

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LISS

Low Ionic Strength Solution that reduces ionic strength to enhance antibody proximity.

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Albumin

A protein stabilizer that reduces repulsion between charged red blood cells.

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PEG

Polyethylene Glycol that increases viscosity, concentrating red blood cells and antibodies.

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PBS

Phosphate-buffered saline that enhances agglutination by raising molecular interaction rates.

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IgG

An incomplete antibody that can sensitize but does not form a lattice.

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Monoclonal Antibodies

Antibodies targeted at a single antigen, produced from one clone.

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Polyclonal Antibodies

Antibodies produced from multiple clones targeting different antigens.

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Study Notes

Red Blood Cell (RBC) Structure and Function

  • RBCs are crucial for normal survival and function. Their structure and chemistry are studied in three key areas.
  • The RBC membrane is a semipermeable lipid bilayer. A protein cytoskeleton supports this structure.
  • Integral proteins span the membrane, while peripheral proteins are limited to the membrane's cytoplasmic surface.
  • Glycophorin is a membrane protein; about 20% of the membrane is glycophorin. Sialic acid in glycophorin gives cells a negative charge to prevent cell clumping.
  • Proteins make up approximately 52% of the RBC membrane, lipids 40%, and carbohydrates 8%.
  • Spectrin, ankyrin, actin, and protein 4.1 are examples of peripheral proteins.
  • During fetal development, globin gene activation progresses from Zeta to Alpha to Epsilon to Gamma to Delta to Beta.
  • Important for gas transport. In the lungs oxygen is delivered to the tissues, where carbon dioxide is released.

RBC Deformability and Permeability

  • RBCs must remain flexible to remain viable.
  • Loss of ATP (adenosine triphosphate) causes a decrease in spectrin phosphorylation, impacting membrane flexibility.
  • Calcium accumulation increases membrane rigidity. This results in cells like spherocytes and bite cells.
  • RBC membranes freely allow water and anions (like Cl- and HCO3-) to pass. However, they resist cations (like Na+ and K+).

RBC Metabolism

  • RBC metabolic pathways primarily function aerobically. The primary function is oxygen delivery, not consumption.
  1. Ten percent of ATP is generated by the pentose phosphate pathway. Depletion of NADPH during oxidative stress can affect globin chain degradation, and Heinz bodies inclusions are formed.
  2. Methemoglobin reductase pathway maintains hemoglobin in its ferrous (Fe2+) state; dependence on NADPH; deficient O2 transport if pathway is compromised (hypoxia).
  3. Luebering-Rapoport shunt creates (2,3-DPG), which affects hemoglobin-oxygen binding, facilitating tissue oxygen release.

Effect of 2,3-DPG

  • 2,3-DPG decreases hemoglobin's oxygen affinity, leading to easier oxygen release in tissues.
  • When hemoglobin releases oxygen, it shifts to a less stable T-state.
  • When hemoglobin binds oxygen, it shifts to a more stable R-state, increasing its oxygen affinity.

Conditions Affecting Oxygen Dissociation Curve

  • A rightward shift of the oxygen dissociation curve indicates decreased oxygen affinity. A leftward shift indicates increased oxygen affinity.
  • Conditions causing rightward shifts include anemia, acidosis (lower pH), increased 2,3-DPG, and fever.
  • Conditions causing leftward shifts include multiple transfusions of stored blood, alkalosis (higher pH), decreased 2,3-DPG, and hypothermia.
  • Stored blood often has low 2,3-DPG levels; this makes it harder for hemoglobin to release oxygen in tissues.

RBC Storage

  • More than 75% of transfused RBCs need to survive 24 hours after storage based on FDA requirements.
  • Stored blood characteristics include decreased viable cell count, glucose, ATP, and pH. Increased lactic acid and K+ levels.

Preservatives

  • Adenine is incorporated into CPDA-1 to drive glycolysis, increasing ATP levels.
  • Adenine-supplemented blood can be stored at 1°C–6°C for 35 days.
  • Other anticoagulants are typically approved for storage for up to 21 days.
  • Preservative solutions address nutrient loss due to plasma removal in RBCs, crucial for viability.

RBC Freezing

  • Red blood cell freezing is mainly for autologous units and rare blood types.
  • Glycerol is added to RBCs before freezing; this protects cells.
  • Glycerol is mixed with RBCs by shaking.
  • Frozen RBCs are typically stored at -65 °C.
  • A 10-year storage period is FDA-alllowed.
  • Deglycerolization process removes glycerol before transfusion, preventing damage.
  • High concentrations of Glycerol are more common (40%)
  • Low concentrations are also used (20%).

RBC Washing Steps

  • Washing steps involve successive washes with 12%, 1.6%, and 0.2% dextrose in normal saline, used for removal of antibodies and serum proteins.

RBC Typing

  • ABO blood typing determines the presence of A and B antigens on red blood cells.
  • Antibodies are used to identify unknown antibodies, resulting in agglutination when antigens are present on the red blood cells.

Reagent Preparation

  • 10% bleach is used for disinfection and contamination surface.
  • 0.85% saline is used to wash cells to prevent lysis; it's isotonic to RBCs.

Cell Washing (Suspension)

  • Used to remove unbound antibodies and serum proteins that could interfere with agglutination, and to ensure cells are free from plasma proteins.

Coomb's Check Cells (CCC)

  • Used to validate a negative AHG test (not for checking antibodies in red blood cells).
  • The tests (direct and indirect) assess for antibodies attached to cells. Positive blood is used for CCC.

Antibody Excess (Prozone) Effect

  • Antibody excess in a sample results in a false-negative result if excess antibodies are present.

Platelet Structure

  • Platelets contain granules—alpha, dense, and lysosomes. These contain various substances like ADP, ATP, calcium, and serotonin.

Platelet Viability and Storage

  • Platelets typically live 8–10 days. Storage is at 20°C-24°C, maintaining correct pH is important.
  • Platelets are activated during storage, leading to degranulation, lactate increase, ATP decrease and pH decrease.
  • Bacteria contamination is a concern; storage is limited to 5 days in the U.S. and rapid tests are available.
  • Frozen platelets can be stored up to 2 years but with significant decrease in recovery (33%).

Platelet Transfusions and Limitations

  • Platelet transfusions are needed for patients with low platelet counts (thrombocytopenia).
  • Corrected count increment (CCI) measures platelet level rise after transfusion but does not evaluate platelet function.
  • False negatives can result from cells being packed together during centrifugation and need to avoid rouleaux.

Potentiation for Agglutination

  • Chemicals like LISS (low ionic strength solution), albumin, PEG, (polyethylene glycol), PBS (phosphate-buffered saline) and warm saline can enhance agglutinization reactions.
  • Potentiation helps antibodies to bind to the antigen and promote cell agglutination.

IgG and AHG

  • IgG is an incomplete antibody that needs the AHG phase for detection.
  • IgG sensitization alone does not create enough lattice formation for detection.

Clinical Significance of Antibodies

  • Anti-A, Anti-B, Anti-D (Rh), Anti-K, and Anti-Duffy antibodies are clinically significant.

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Description

Explore the intricacies of red blood cell structure, function, and metabolism. This quiz covers essential proteins, oxygen binding, blood storage, and factors affecting RBC survival. Learn about hemoglobin and its role in oxygen transport.

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