IMMUNOSEROLOGY
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Questions and Answers

What is the maximum age for an allogeneic donor according to the criteria, if the state law does not specify a maximum age?

  • 70 years
  • 65 years
  • 80 years
  • No maximum age (correct)

    • Which of the following medications irreversibly affects platelet function and is mentioned in the context of platelet pooling?

  • Warfarin
  • Clopidogrel
  • Aspirin (correct)
  • Heparin

    • What is the minimum weight criterion for an allogeneic donor?

  • 100 lb / 45 kg
  • 130 lb / 60 kg
  • 110 lb / 50 kg (correct)
  • 120 lb / 55 kg

    • What is the maximum oral temperature allowed for an allogeneic donor?

    <p>37.5°C</p> Signup and view all the answers

    Which blood pressure reading was previously defined by AABB but is now determined by the institution?

    <p>180/100 mmHg</p> Signup and view all the answers

    What hemoglobin level is required as a minimum for an allogeneic donor?

    <p>12.5 g/dL</p> Signup and view all the answers

    What is the maximum amount of whole blood that can be collected per kilogram of body weight from a donor?

    <p>10.5 mL</p> Signup and view all the answers

    What is the recommended donor interval for whole blood donation?

    <p>8 weeks</p> Signup and view all the answers

    How long should the site be scrubbed before the collection of donor blood?

    <p>30 seconds</p> Signup and view all the answers

    Who must evaluate the medications of a potential donor?

    <p>Medical Doctor (MD)</p> Signup and view all the answers

    Which of the following is NOT listed as a step in the collection of donor blood?

    <p>Brand recommendation</p> Signup and view all the answers

    What technique should be used to ensure a sterile collection site?

    <p>Iodine scrub</p> Signup and view all the answers

    Which of these statements about donor blood collection is incorrect?

    <p>Whole blood can be collected from donors every 6 weeks.</p> Signup and view all the answers

    What is a consideration that must be addressed during the donor selection process?

    <p>Donor's previous donation history</p> Signup and view all the answers

    What is the maximum duration for which CPDA-1 can be effective as an anticoagulant?

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

    Which of the following conditions does NOT indicate a donor deferral due to bloodborne pathogen risk?

    <p>History of hypertension</p> Signup and view all the answers

    What is the primary purpose of rejuvenating solutions in blood storage?

    <p>To restore 2, 3-DPG and ATP</p> Signup and view all the answers

    Which of the following is NOT a characteristic of autologous blood donations?

    <p>Donor must be hepatitis-negative</p> Signup and view all the answers

    What happens to a unit of blood if a rejuvenating solution is used and not frozen within 24 hours?

    <p>It can be stored at 1-6°C but requires washing before transfusion</p> Signup and view all the answers

    Which process specifically refers to the separation and collection of plasma from whole blood?

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

    How long can blood units with additives be stored effectively?

    <p>42 days</p> Signup and view all the answers

    Which component of blood does cytapheresis primarily collect?

    <p>White blood cells</p> Signup and view all the answers

    What is a reason for deferring a potential blood donor for one year?

    <p>Tattoo from a non-regulated facility</p> Signup and view all the answers

    Which of the following is NOT a criterion for a one-year donor deferral?

    <p>Having a body piercing at a licensed facility</p> Signup and view all the answers

    What deferral period applies to a donor with a previous diagnosis of malaria?

    <p>3 years</p> Signup and view all the answers

    Which condition would result in an indefinite deferral from donating blood?

    <p>Past infection of hepatitis C</p> Signup and view all the answers

    What is the duration of deferral for a donor who had mucous membrane exposure to blood?

    <p>1 year</p> Signup and view all the answers

    Which of the following scenarios leads to an indefinite deferral due to the risk of bloodborne pathogens?

    <p>Confirmed positive test for anti-HTLV</p> Signup and view all the answers

    What is a common deferral reason for a potential donor that involves sexual contact?

    <p>Sexual contact with someone symptomatic for any viral hepatitis</p> Signup and view all the answers

    What duration of deferral applies for someone with a tattoo done in a regulated facility?

    <p>No deferral</p> Signup and view all the answers

    If a recipient developed post-transfusion hepatitis, what is the deferral consequence for the donor?

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

    What is the temperature threshold above which a unit of blood cannot be returned and reissued?

    <p>10°C</p> Signup and view all the answers

    Which of the following indicates a procedure to process washed red cells?

    <p>Saline washes with an automated instrument</p> Signup and view all the answers

    What significant test is performed to resolve discrepancies in donor blood processing?

    <p>Weak D determination</p> Signup and view all the answers

    What role do clinically significant antibodies play in donor blood processing?

    <p>They indicate potential transfusion reactions.</p> Signup and view all the answers

    What component is primarily focused on when conducting a plasma removal procedure in blood processing?

    <p>Red cell integrity</p> Signup and view all the answers

    Which factor is NOT relevant if the seal of a blood unit is disturbed during processing or storage?

    <p>Presence of leukocytes in the blood unit</p> Signup and view all the answers

    What is the primary purpose of apheresis red blood cells?

    <p>To ensure hemoglobin levels exceed 60g</p> Signup and view all the answers

    What is the consequence of breaking the seal on the original unit of blood?

    <p>The expiration date shortens to 24 hours</p> Signup and view all the answers

    Which component can be prepared from a unit of blood primarily used to prevent allergic reactions?

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

    What is the key characteristic of IgA deficient patients treated to prevent anaphylactic shock?

    <p>They receive blood products with anti-IgA removed</p> Signup and view all the answers

    What type of testing is performed to identify the presence of Hepatitis C in blood donations?

    <p>NAT Testing</p> Signup and view all the answers

    What is the role of complement removal in maternal blood preparation for neonatal transfusions?

    <p>To prevent transfusion reactions</p> Signup and view all the answers

    What is the expected reaction when testing a Bombay phenotype with Anti-H serum?

    <p>No agglutination occurs with Anti-H serum.</p> Signup and view all the answers

    What laboratory finding is typically associated with Rouleaux formation?

    <p>Increased serum proteins.</p> Signup and view all the answers

    Which of the following scenarios might enhance the detection of antibodies in a 'Mini' Cold Panel?

    <p>Testing at lower temperatures.</p> Signup and view all the answers

    In elderly patients, what is a common problem related to antibody production?

    <p>Underproduction of antibodies.</p> Signup and view all the answers

    What type of antibodies may react with cells in patients with a cold-reacting antibody phenomenon?

    <p>Cold-reacting antibodies only.</p> Signup and view all the answers

    What condition may cause antibody production not to reach optimal levels in newborns?

    <p>Underdeveloped immune system.</p> Signup and view all the answers

    Which antibody is specifically associated with unexpected reactions at colder temperatures?

    <p>Anti-I</p> Signup and view all the answers

    What is the primary purpose of using saline replacement in testing?

    <p>To differentiate between rouleaux and agglutination</p> Signup and view all the answers

    Which cells must be transfused in the case of an ABO discrepancy until it is resolved?

    <p>Group O cells</p> Signup and view all the answers

    In a Mini Cold Panel, which test is expected to react with O cells when testing for anti-H, -M, -N, -P I, and Lewis antibodies?

    <p>O Cells</p> Signup and view all the answers

    What is the significance of testing with O Cord Cells when available?

    <p>To enhance the detection of cold antibodies</p> Signup and view all the answers

    Which of the following antibodies would NOT be expected in a Mini Cold Panel?

    <p>Anti-Rh</p> Signup and view all the answers

    When performing serum tests, what result indicates the presence of anti-A or anti-B antibodies?

    <p>Positive reaction with A/B Cells</p> Signup and view all the answers

    What reaction does saline replacement help clarify during blood testing?

    <p>Normal agglutination vs. Rouleaux formation</p> Signup and view all the answers

    What result indicates that the unknown cells possess the corresponding antigen for anti-A sera?

    <p>Agglutination with anti-A</p> Signup and view all the answers

    Which blood group is indicated by the reagents showing '+' with anti-A and '0' with anti-B?

    <p>Group A</p> Signup and view all the answers

    Which statement is true regarding subgroups like A3 and Ax in relation to antigen types?

    <p>They contain less A antigen and more H antigen.</p> Signup and view all the answers

    What does '0' signify in a blood typing test with both anti-A and anti-B reagents?

    <p>The absence of both A and B antigens.</p> Signup and view all the answers

    What conclusion can be drawn if there is agglutination with both anti-A and anti-B reagents?

    <p>The sample belongs to Group AB.</p> Signup and view all the answers

    What interpretation can be made from unknown cells that show no agglutination with any antisera?

    <p>The cells lack antigens for both A and B.</p> Signup and view all the answers

    In serum typing, what does the designation 'Anti-A' specifically relate to?

    <p>Antibodies against A antigens.</p> Signup and view all the answers

    What is the expected result when testing a Group B blood sample against anti-B reagents?

    <p>Agglutination with anti-B.</p> Signup and view all the answers

    Which statement about Rh antibodies is correct?

    <p>IgG forms of Rh antibodies can agglutinate at 37C.</p> Signup and view all the answers

    What problem may arise when using enzyme-treated cells with anti-C or anti-E antibodies?

    <p>Decreased reactivity with clinically significant antibodies.</p> Signup and view all the answers

    What is true regarding Lewis blood group antigens?

    <p>Plasma antigens can adsorb onto red blood cells.</p> Signup and view all the answers

    Which statement about storage effects on P1 antigen is accurate?

    <p>P1 antigen strength deteriorates upon storage.</p> Signup and view all the answers

    How does prewarming affect the activity of antibodies?

    <p>It can decrease the activity of some clinically significant antibodies.</p> Signup and view all the answers

    Which antibodies are considered cold antibodies that may not always react at body temperature?

    <p>Anti-P1 and other IgM antibodies.</p> Signup and view all the answers

    What characteristic is associated with allogeneic and autoadsorption methods?

    <p>Recent transfusions can interfere with autoadsorption.</p> Signup and view all the answers

    What is the potential risk when using IgG AHG for adsorption?

    <p>It can lead to missed detection of weak antibodies.</p> Signup and view all the answers

    Which statement about Anti-I is correct?

    <p>Anti-I can cause delayed transfusion reactions.</p> Signup and view all the answers

    What is true regarding Anti-M?

    <p>Anti-M requires acidification of serum for identification.</p> Signup and view all the answers

    Which of the following accurately describes Anti-U?

    <p>68% of African Americans may lack the U antigen.</p> Signup and view all the answers

    What characterizes the KELL blood group antigens?

    <p>91% of individuals in the KELL group are K negative.</p> Signup and view all the answers

    Which scenario correctly describes the interactions of Anti-S and anti-s antibodies?

    <p>Anti-S is less likely to rise and fall rapidly in titer.</p> Signup and view all the answers

    How do dosage effects relate to Anti-M antibodies?

    <p>Anti-M antibodies demonstrate stronger reactivity in homozygous conditions.</p> Signup and view all the answers

    What is the implication of enzyme treatment on Duffy antigens?

    <p>Duffy antigens are destroyed by enzyme treatment.</p> Signup and view all the answers

    What can be inferred about the antibody types and their associated reactions?

    <p>IgG antibodies are typically associated with delayed transfusion reactions.</p> Signup and view all the answers

    Which reagents are known to destroy or weaken Kell system antigens?

    <p>ZZAP and AET</p> Signup and view all the answers

    What is the main role of performing a 'last wash' control prior to elution?

    <p>To ensure no residual serum antibody contamination</p> Signup and view all the answers

    What result indicates serum antibody contamination during the 'last wash' test?

    <p>Positive test results with reagent cells</p> Signup and view all the answers

    Which method is effective for removing IgG from RBCs but does not affect complement?

    <p>Chloroquine diphosphate</p> Signup and view all the answers

    Which of the following techniques cleaves disulfide bonds to reduce IgM activity?

    <p>DTT and 2-ME</p> Signup and view all the answers

    Which statement is true regarding the effect of acid or organic solvent methods on antibodies?

    <p>They work best for both auto- and allo-reacting antibodies.</p> Signup and view all the answers

    What effect does the 'last wash' showing no reactivity have on testing results?

    <p>Indicates effective elution of antibodies</p> Signup and view all the answers

    What is the significance of using DTT in blood processing?

    <p>It destroys or diminishes the activity of IgM antibodies.</p> Signup and view all the answers

    What is the purpose of autoadsorption in antibody testing?

    <p>To separate and identify alloantibody specificity</p> Signup and view all the answers

    Which statement accurately describes allogeneic adsorption technique?

    <p>It is suitable for patients recently transfused to identify hidden antibodies.</p> Signup and view all the answers

    What is the optimal sample type used for a Direct Antiglobulin Test (DAT)?

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

    What indicates a positive reaction in the column agglutination (gel testing)?

    <p>Cells adhering to the sides of the microwell plate</p> Signup and view all the answers

    Which type of Antihuman Globulin (AHG) is derived from immunized animals targeting multiple epitopes?

    <p>Polyclonal AHG</p> Signup and view all the answers

    What is one of the primary uses of adsorption in serological work?

    <p>To enhance the sensitivity of antibody detection</p> Signup and view all the answers

    In what scenario is autoadsorption particularly recommended?

    <p>For patients who have not been transfused recently</p> Signup and view all the answers

    What happens if cells are coated in vivo during a DAT?

    <p>Antiglobulin will react with IgG antibodies or complement.</p> Signup and view all the answers

    What is the primary purpose of washing cells multiple times before adding antiglobulin in a DAT?

    <p>To remove plasma proteins that may cause false positives.</p> Signup and view all the answers

    What is a key characteristic of positive reactions in gel testing?

    <p>Agglutinated cells do not settle, indicating reaction</p> Signup and view all the answers

    Why is it important to interpret eluate results in antibody testing?

    <p>To confirm antibody specificity and presence of antigens</p> Signup and view all the answers

    Which statement about monoclonal AHG is true?

    <p>It is produced from hybridomas.</p> Signup and view all the answers

    What is a consequence of using EDTA as an anticoagulant in blood samples?

    <p>It chelates calcium, preventing complement activation.</p> Signup and view all the answers

    What problem might arise when testing eluate results?

    <p>Misinterpretation due to the presence of interfering substances</p> Signup and view all the answers

    What does agglutination in a DAT indicate?

    <p>Antibodies may be coating the patient's red blood cells.</p> Signup and view all the answers

    What is required for patients with significant antibodies prior to blood transfusion?

    <p>They must only receive antigen-negative units that are crossmatch compatible.</p> Signup and view all the answers

    Which reagent is essential for the reaction in the Direct Antiglobulin Test?

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

    What method is used to calculate the probability of finding antigen-negative blood units?

    <p>Multiply the percentage of each specific antigen negative unit.</p> Signup and view all the answers

    Which of the following statements about plasma transfusion is accurate?

    <p>Group O recipients can receive type A, AB, or AH plasma.</p> Signup and view all the answers

    What factor is particularly emphasized in transfusions involving women of childbearing age?

    <p>Confirmatory tests must align with the donor's label.</p> Signup and view all the answers

    How should plasma transfusion decisions be made?

    <p>By ensuring plasma does not contain corresponding antibodies to the recipient's blood type.</p> Signup and view all the answers

    In a situation where antigen-negative units are needed, what would be a reasonable expectation regarding availability?

    <p>Only a small percentage of antigen-negative units will be available.</p> Signup and view all the answers

    What is the purpose of adding check cells during the evaluation of incompatible crossmatch results?

    <p>To confirm the adherence of antibodies to antigens</p> Signup and view all the answers

    Which of the following describes the order of operations when performing antibody or antigen testing on a microwell plate?

    <p>Fix antibody, wash, add antigen, add plasma</p> Signup and view all the answers

    What information is considered clinically significant when preparing for blood typing?

    <p>List of clinically significant antibodies</p> Signup and view all the answers

    In the solid phase technique, what is the role of an antigen adhering to an antibody on the sides of the microwell?

    <p>Provides a specific site for the detection of antibodies</p> Signup and view all the answers

    What aspect must be compared to assess the reliability of current test results?

    <p>Prior tests and any difficulties encountered</p> Signup and view all the answers

    Which component is least likely to be involved in the reaction observed when plasma is added to a microwell plate containing antigen?

    <p>Filler solution for the microwell</p> Signup and view all the answers

    What is the minimum consideration regarding QC when using antisera for testing?

    <p>Ensuring antisera is from a reliable source and used on the day of testing</p> Signup and view all the answers

    Which factor is NOT part of the pre-testing evaluation for blood typing?

    <p>Presence of any current symptoms in the donor</p> Signup and view all the answers

    What is a key characteristic used to indicate severe hemolytic reactions in transfusions?

    <p>Positive direct antiglobulin test (DAT)</p> Signup and view all the answers

    Which of the following scenarios describes a delayed transfusion reaction?

    <p>Symptoms showing within hours to days after transfusion</p> Signup and view all the answers

    What is the primary reason for issuing antigen-negative blood for transfusions to infants?

    <p>To prevent Rh incompatibility</p> Signup and view all the answers

    Which blood type recipients can typically receive RBCs from type B donors?

    <p>Type B and AB</p> Signup and view all the answers

    Which of the following antibodies is commonly associated with delayed transfusion reactions?

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

    What significant symptom complex characterizes transfusion-related acute lung injury (TRALI)?

    <p>Bilateral pulmonary edema without cardiac failure</p> Signup and view all the answers

    What is a common physiological event associated with transfusion reactions?

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

    How does a positive direct antiglobulin test (DAT) influence transfusion procedures?

    <p>Mandates antigen-negative blood for the infant</p> Signup and view all the answers

    Which condition must be tested in neonates for safe blood transfusion?

    <p>ABO group and unexpected antibodies</p> Signup and view all the answers

    Which symptom is most commonly associated with delayed transfusion reactions?

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

    What lab procedure is necessary to resolve discrepancies in donor blood processing?

    <p>Antiglobulin crossmatch</p> Signup and view all the answers

    What consequence occurs when ABO incompatible blood is transfused into a recipient with maternal antibodies?

    <p>Immediate hemolytic reaction</p> Signup and view all the answers

    What can be a direct consequence of extravascular hemolytic reactions?

    <p>Acute kidney injury</p> Signup and view all the answers

    What type of error usually leads to transfusion reactions related to blood types?

    <p>Clerical errors in blood type documentation</p> Signup and view all the answers

    What is the primary method used to test for unexpected antibodies in infants?

    <p>Mother's serum or infant's serum</p> Signup and view all the answers

    What complication can occur due to hyperbilirubinemia in transfusion reactions?

    <p>Kidney failure</p> Signup and view all the answers

    Study Notes

    Donor Selection and Blood Collection

    • Initial steps include registration, medical history, and physical examination of the donor.
    • Aseptic technique requires scrubbing the site for a minimum of 30 seconds with providine-iodine.

    General Information

    • Maximum blood collection is limited to 10.5 mL per kilogram of body weight, including samples.
    • A minimum interval of 8 weeks is required between whole blood donations.
    • Medications impacting platelet function must be evaluated by a medical doctor.

    Criteria for Allogeneic Donor Selection

    • Age: Donors must be at least 16 years old, with no maximum age limit subject to physician evaluation.
    • Temperature: Oral temperature must be ≤ 37.5°C (99.5°F).
    • Blood Pressure: No longer specifically defined; institutions set their own standards.
    • Hemoglobin/Hematocrit: Minimum levels are 12.5 g/dL and 38% respectively.
    • Weight: Donors must weigh at least 110 lbs (50 kg).

    Donor Deferral

    • 1 Year Deferral: Includes exposures to hepatitis, HIV, and malaria; tattoos from non-regulated facilities; and sexual exposure to individuals positive for hepatitis or HIV.
    • 3 Year Deferral: Visitors or immigrants from malaria-endemic areas; previous malaria diagnosis.
    • Indefinite/Permanent Deferral: History of viral hepatitis after age 11, confirmed positive tests for hepatitis or HIV, and evidence of parenteral drug use.

    Common Anticoagulants and Additives

    • Expiration:
      • ACD/CPD/CPD2: 21 days
      • CPDA-1: 35 days
      • Additives: 42 days
    • Rejuvenating Solutions:
      • Restore 2, 3-DPG and ATP levels.
      • Units can be frozen or stored at 1-6°C for 24 hours before transfusion.

    Autologous Donations

    • Autologous donations are for personal use with no age limit.
    • Minimum standards: Hematocrit ≥ 33% and Hemoglobin ≥ 11 g/dL.
    • Must not have bacteremia.

    Donor Blood Processing

    • Blood processing involves multiple tests to ensure safety and compatibility.
    • Key tests include:
      • pH levels
      • Sodium (Na+) evaluation
      • Weak D determination
      • Serological testing for specific antibodies such as Anti-HIV, Anti-HCV, HBV markers, and syphilis antibodies.

    Changes in Plasma During Storage

    • Plasma experiences changes during storage, particularly at temperatures between 1-6°C.
    • If the unit of blood is stored above 10°C or if the seal is disturbed, it cannot be returned or reissued.

    Washed Red Cell Preparation

    • Plasma is removed from red blood cells through automated saline washes.
    • This method is primarily utilized to prevent allergic reactions to plasma proteins, particularly in patients with IgA deficiency.
    • Important for the safety of neonatal transfusions, as it removes potentially harmful antibodies from maternal blood.

    Expiration and Storage Regulations

    • Washed red cells expire 24 hours after the original unit's seal is broken, reinforcing the importance of proper storage conditions.

    Apheresis Red Blood Cells

    • Hemoglobin concentration in apheresis red blood cells should be greater than 60g to qualify for use.

    Reagents and Agglutination Testing

    • Anti-A and Anti-B reagents are used to determine blood groups through agglutination testing.
    • Testing typically occurs at room temperature and identifies the presence or absence of specific antigens on red blood cells.
    • Lack of agglutination implies that unknown cells do not possess the corresponding antigen.

    Blood Group Interpretation

    • Cells can contain subgroups like A3 or Ax, which have reduced A antigen and increased H antigen.
    • Results for blood grouping:
      • Anti-A positive (+) and Anti-B negative (0) indicates Group A.
      • Anti-A negative (0) and Anti-B positive (+) indicates Group B.
      • Anti-A positive (+) and Anti-B positive (+) indicates Group AB.
      • Anti-A negative (0) and Anti-B negative (0) indicates Group O.

    Serum Typing (Reverse Typing)

    • Reverse typing is used to confirm serological blood group through the reaction of serum with specific cells.
    • Bombay phenotype lacks H antigen; thus does not agglutinate with Anti-H and reacts with A1 and B cells.
    • Conditions like leukemia may affect serum antibodies.

    Common Serum Problems

    • Rouleaux formation can occur due to increased serum proteins and is seen in conditions such as Waldenstrom's or multiple myeloma.
    • Cold reacting antibodies (e.g., anti-H, anti-I, anti-M) may cause reactions when tested at room temperature.
    • An elderly patient may show decreased antibody production, while newborns might not have developed optimum antibody levels.

    ABO Discrepancy Management

    • In cases of ABO discrepancy, transfusion of group O cells is advised until the issue is resolved.

    Mini Cold Panel Principle

    • Mini cold panels enhance the detection of anti-A and anti-B antibodies at lower temperatures and identify "cold" antibodies reacting with A1 and B cells.

    Saline Replacement Use

    • Saline replacement helps differentiate between rouleaux and true agglutination.
    • Assess the presence of non-transfused 'deleted' cells in Rh typing.

    Rh Antibodies and Their Characteristics

    • IgG antibodies are clinically significant and may react at 37°C as well as with anti-human globulin (AHG).
    • Specific anti-C, -c, -E antibodies show stronger reactions with enzyme-treated cells.

    Lewis Blood Group System

    • Lewis antigens (Lea, Leb) are plasma antigens that adsorb onto RBCs; they are absent in cord blood.
    • Antibodies such as anti-P1 and anti-I can exist as cold IgM antibodies; they show dosage and may not react with enzyme-treated cells.

    Antibody Characteristics by Blood Type

    • Anti-M and anti-S are often IgG antibodies that can cause hemolytic disease of the fetus and newborn (HDFN).
    • Duffy antigens (Fy3, Fy4) are co-dominant alleles, with Fya and Fyb being destroyed by enzymes, impacting antigen typing and clinical significance.

    Kell Blood Group System

    • Codominant alleles K and k are part of the Kell system; 91% of individuals are K-negative, affecting transfusion compatibility and antigen typing.

    Antibody Characteristics and Identification

    • Direct Antiglobulin Test (DAT) assesses the presence of antibodies or complement on red blood cells (RBCs).
    • Positive DAT indicates cells coated with antibodies; antiglobulin reacts with IgG or complement.
    • Optimal sample for DAT is EDTA, which prevents complement activation.
    • Various methods exist for antibody inactivation, including sulfhydryl reagents, which can destroy or weaken specific antigens.

    Serological Testing and Methods

    • AHG (Antihuman Globulin) reagents include polyclonal (variety of epitopes) and monoclonal (single epitope) antibodies.
    • Last wash control is essential to minimize serum contamination prior to elution.
    • Positive reactivity in last wash indicates residual serum antibodies; requires retesting.

    Adsorption Techniques

    • Adsorption separates multiple antibodies, removes autoantibodies to reveal underlying alloantibodies.
    • Autoadsorption is suitable for patients recently transfused, while allogeneic adsorptions use donor cells for those not recently transfused.
    • Eluate results help confirm antibody specificity and antigen presence on RBCs.

    Additional Technologies for Detecting Antigen-Antibody Reactions

    • Column agglutination and gel testing used for serological work with controlled conditions, autocontrol is not needed.
    • Solid phase testing involves fixing antibodies or antigens to microwell plates, where binding occurs, followed by washing and addition of check cells.

    Evaluating Transfusion Compatibility

    • Crossmatch evaluation is essential for transfusion and involves analyzing any clinically significant antibodies and previous transfusion reactions.
    • D-negative individuals should only receive D-negative RBCs; emergencies may allow administering D-positive if necessary.
    • Antigen typing ensures patients with significant antibodies receive antigen-negative compatible units.

    Plasma Transfusion Guidelines

    • Plasma transfusions should match patient antibodies; AB plasma can be given to any blood group, while Group O can receive other types.
    • Probability calculations help in identifying compatible units by assessing antigen-negative percentages.

    Blood Transfusion Considerations

    • Recipients of red blood cells (RBCs) and plasma must be identified based on ABO and Rh compatibility to avoid transfusion reactions.
    • Clerical errors in transfusion processes are common with the ABO system, potentially leading to serious complications.
    • The most frequent symptom of a transfusion reaction is fever.

    Physiological Events in Transfusion Reactions

    • Hemoglobinemia: Presence of free hemoglobin in the blood.
    • Hemoglobinuria: Hemoglobin in urine, indicating renal damage.
    • Hyperbilirubinemia: Elevated bilirubin levels due to hemolysis.
    • Severe outcomes can include kidney failure and potentially death.

    Neonatal Crossmatch Protocol

    • Initial testing for neonates under 4 months involves determining ABO group and Rh type.
    • Unexpected antibodies testing can be performed using either the infant's or mother's serum/plasma.
    • No crossmatch or repeat ABO/Rh testing is required for neonates during hospitalization if the initial antibody screen is negative.
    • Blood given should be group "O", ABO identical, or compatible, and D compatible.

    Delayed Transfusion Reactions

    • Often result from anamnestic responses to significant antibodies like Rh, Kell, Kidd, and Duffy, occurring after transfusion completion.
    • Symptoms can manifest hours to days post-transfusion with no expected increase in hemoglobin levels.
    • A positive Direct Antiglobulin Test (DAT) is a key indicator, often associated with Kidd antibodies.
    • Characterized by acute respiratory insufficiency and bilateral pulmonary edema observable in X-ray results.
    • Symptoms typically include chills, fever, hypotension, and no indication of cardiac failure.

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    Related Documents

    Immunohematology Donor Selection and Blood Collection PDF
    Donor Blood Processing PDF
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