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ABPath Blood Banking/Transfusion Medicine study materials
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ABPath Blood Banking/Transfusion Medicine practice questions

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Question 1Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the minimum acceptable hemoglobin (or hematocrit) for an allogeneic whole blood donor at the time of donation?

  1. 11.0 g/dL or 33%
  2. 13.0 g/dL or 39% Correct answer.
  3. 12.0 g/dL or 36%
  4. 12.5 g/dL or 38%

Explanation

AABB standards require a minimum hemoglobin of 13.0 g/dL or hematocrit of 39% for allogeneic whole blood donors, measured on a sample obtained at the time of donation. This threshold protects donors from iron depletion and anemia.

Question 2Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor's oral temperature is 37.3 °C (99.1 °F) and the donor otherwise feels well. How should this affect eligibility for whole blood donation?

  1. Defer until afebrile for at least 7 days
  2. Defer permanently
  3. Defer for 12 months
  4. Accept the donor, since the temperature is within the acceptable limit Correct answer.

Explanation

Donors must be afebrile; an oral temperature no higher than 37.5 °C (99.5 °F) is generally acceptable. A reading of 37.3 °C is within limits and does not require deferral.

Question 3Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which parameter is used to determine the minimum interval between whole blood donations in the United States?

  1. A fixed 56-day interval regardless of volume
  2. An interval based solely on the donor's hemoglobin at the prior donation
  3. A calculated interval based on the volume of red cells lost and donor weight Correct answer.
  4. A 28-day interval for all donors

Explanation

The interval is calculated from the estimated red cell (iron) loss relative to donor weight, yielding a minimum of 8 weeks (56 days) for most donors but longer for smaller donors. This approach protects donor iron stores.

Question 4Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the acceptable range for the volume of a whole blood collection (including anticoagulant) when a standard 500 mL bag is used?

  1. 500 to 600 mL
  2. 350 to 450 mL
  3. 406 to 495 mL
  4. 450 to 550 mL Correct answer.

Explanation

A standard whole blood collection with 500 mL bag and 70 mL anticoagulant should total approximately 450 to 550 mL. Collections outside this range may be unsuitable for component preparation.

Question 5Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

During a whole blood collection, how often should the collection bag be mixed to ensure adequate anticoagulant distribution?

  1. Once at the beginning and once at the end
  2. Only when the bag reaches 200 mL
  3. Every 5 minutes
  4. Continuously or at intervals of no more than 45 seconds Correct answer.

Explanation

The bag must be mixed during collection, typically continuously or at intervals not exceeding 45 seconds, to prevent clot formation. Inadequate mixing can render the unit unsuitable.

Question 6Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which anticoagulant-preservative solution is associated with a whole blood storage period of 35 days at 1 to 6 °C?

  1. AS-1
  2. CP2D
  3. CPDA-1 Correct answer.
  4. CPD

Explanation

CPDA-1 adds adenine to extend whole blood storage to 35 days at 1 to 6 °C. CPD and CP2D allow 21 days, and additive solutions apply to red cell units rather than whole blood.

Question 7Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Whole blood intended for transfusion as whole blood must be stored at what temperature?

  1. -18 °C or colder
  2. 20 to 24 °C
  3. 10 to 15 °C
  4. 1 to 6 °C Correct answer.

Explanation

Whole blood is stored at 1 to 6 °C to maintain red cell viability and limit bacterial growth. Room temperature storage does not preserve red cells for transfusion.

Question 8Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which component is prepared by centrifuging whole blood and removing plasma within a closed system to yield a product with a hematocrit of roughly 55 to 80%?

  1. Cryoprecipitate
  2. Leukoreduced whole blood
  3. Platelet concentrate
  4. Red blood cells Correct answer.

Explanation

Red blood cells are prepared by removing plasma from whole blood, giving a hematocrit of approximately 55 to 80% depending on the method. This concentrates the red cells for transfusion.

Question 9Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A unit of whole blood is collected and processed. Within what time frame should it be centrifuged to prepare platelet-rich plasma for platelet production when stored at room temperature?

  1. Within 72 hours of collection
  2. Within 24 hours of collection
  3. Within 8 hours of collection Correct answer.
  4. There is no time limit if refrigerated

Explanation

To prepare platelets, whole blood should be processed within 8 hours of collection when held at room temperature. Prompt processing preserves platelet viability and function.

Question 10Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the primary indication for transfusing whole blood rather than a red cell component?

  1. Chronic anemia in an outpatient setting
  2. Isolated thrombocytopenia
  3. Massive hemorrhage with concurrent volume loss Correct answer.
  4. Factor VIII deficiency

Explanation

Whole blood is indicated when both oxygen-carrying capacity and volume expansion are needed, such as massive hemorrhage. Component therapy is preferred for most other indications.

Question 11Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor reports taking aspirin daily. How does this affect eligibility to donate whole blood?

  1. Permanent deferral
  2. Deferral until 7 days after the last dose
  3. No deferral for whole blood donation Correct answer.
  4. 12-month deferral

Explanation

Aspirin affects platelet function but does not disqualify a whole blood donor. The donor may donate, although the platelets may not be suitable for transfusion if platelet function is required.

Question 12Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which donor is acceptable for whole blood donation based on vital signs alone?

  1. Diastolic blood pressure 110 mm Hg
  2. Pulse 110 beats per minute and regular
  3. Systolic blood pressure 185 mm Hg
  4. Pulse 80 beats per minute and regular Correct answer.

Explanation

Acceptable limits are a pulse between 50 and 100 beats per minute (regular) and blood pressure no greater than 180/100 mm Hg. A pulse of 80 is within range.

Question 13Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the minimum donor weight requirement for a standard whole blood donation in the United States?

  1. 55 kg (121 lb)
  2. 45 kg (99 lb)
  3. 60 kg (132 lb)
  4. 50 kg (110 lb) Correct answer.

Explanation

The standard minimum donor weight is 50 kg (110 lb) to limit the proportion of blood volume removed. Donors below this weight may donate only under special collection protocols.

Question 14Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor had a tattoo applied at a regulated facility using sterile needles and single-use ink. What is the appropriate deferral?

  1. 12-month deferral
  2. 6-month deferral regardless of regulation
  3. Permanent deferral
  4. No deferral if the facility is state-regulated Correct answer.

Explanation

Tattoos obtained at state-regulated facilities using sterile technique do not require deferral. Unregulated tattoos generally require a deferral period.

Question 15Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the required storage temperature for red blood cell units after preparation?

  1. -18 °C or colder
  2. 1 to 6 °C Correct answer.
  3. 1 to 10 °C
  4. 20 to 24 °C

Explanation

Red blood cell units are stored at 1 to 6 °C to maintain viability and limit bacterial proliferation. Warmer temperatures shorten shelf life and increase infection risk.

Question 16Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor who lived in a malarial-endemic area returns to the United States. What is the typical deferral period for whole blood donation?

  1. No deferral is needed
  2. 5 years after departure from the endemic area
  3. 3 months after departure from the endemic area Correct answer.
  4. 1 year after departure from the endemic area

Explanation

Donors who have lived in malaria-endemic areas are generally deferred for 3 months after departure from the area. This interval reflects the incubation period of malaria.

Question 17Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which label information is required on a whole blood unit to indicate its storage period and anticoagulant?

  1. Anticoagulant, storage temperature, and expiration date Correct answer.
  2. Donor's weight and pulse
  3. Donor's blood type only
  4. Collection center phone number

Explanation

Component labels must include the anticoagulant used, storage temperature, and expiration date to ensure proper handling. This information allows safe storage and transfusion.

Question 18Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A unit of whole blood is collected from a donor weighing 45 kg. What is the primary concern regarding the collection volume?

  1. The donor may experience hypovolemia if a standard volume is drawn Correct answer.
  2. The unit will be hyperkalemic
  3. The unit will clot immediately
  4. The unit will have excess anticoagulant relative to red cells

Explanation

Donors below the standard minimum weight may not tolerate removal of a standard 450 to 550 mL volume, risking hypovolemia. A reduced-volume collection or special protocol may be used.

Question 19Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the maximum allowable storage time for whole blood collected in CPD at 1 to 6 °C?

  1. 24 hours
  2. 21 days Correct answer.
  3. 42 days
  4. 35 days

Explanation

Whole blood collected in CPD has a shelf life of 21 days at 1 to 6 °C. Adenine-containing solutions extend storage to 35 days.

Question 20Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which donor history finding requires a permanent deferral from whole blood donation?

  1. A dental extraction 3 days ago
  2. A confirmed positive test for HIV Correct answer.
  3. A cold with fever 10 days ago
  4. Travel to a malaria-endemic area 2 months ago

Explanation

A confirmed positive test for HIV results in permanent deferral because of the risk of transfusion-transmitted infection. Other findings listed require temporary deferrals.

Question 21Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A whole blood unit is leukoreduced by filtration. What is the typical residual leukocyte count per unit to meet the standard?

  1. Less than 5 × 10^8
  2. Less than 5 × 10^6 Correct answer.
  3. Less than 5 × 10^2
  4. Less than 5 × 10^4

Explanation

Leukoreduction standards require fewer than 5 × 10^6 leukocytes per unit to reduce febrile reactions and cytomegalovirus transmission. This is the accepted threshold for labeled leukoreduced components.

Question 22Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

Which action is required before a whole blood unit can be released for transfusion after collection?

  1. Confirm donor identity and test for infectious disease markers Correct answer.
  2. Recalculate the collection volume after 24 hours
  3. Perform a crossmatch with the donor's own serum
  4. Repeat the donor's hemoglobin

Explanation

Donor identity must be verified and required infectious disease testing completed before release. These steps ensure traceability and safety of the component.

Question 23Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor reports a history of hepatitis B infection confirmed by a positive HBsAg test 5 years ago. What is the appropriate deferral?

  1. No deferral
  2. 6-month deferral
  3. Permanent deferral Correct answer.
  4. 12-month deferral

Explanation

A history of confirmed hepatitis B infection results in permanent deferral because of the risk of transmission. This applies regardless of the time since infection.

Question 24Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

What is the purpose of adding an additive solution (such as AS-1) to a red blood cell unit?

  1. To increase the hematocrit to 90%
  2. To extend red cell storage to 42 days Correct answer.
  3. To reduce the unit's potassium content immediately
  4. To sterilize the unit

Explanation

Additive solutions provide nutrients that extend red cell storage to 42 days. They support metabolism and maintain viability during prolonged storage.

Question 25Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor is taking a live attenuated vaccine. How long after vaccination should whole blood donation generally be deferred?

  1. 4 weeks Correct answer.
  2. 6 months
  3. 2 weeks
  4. No deferral is needed

Explanation

A 4-week deferral is generally recommended after administration of a live attenuated vaccine. This interval reduces the risk of transmitting the vaccine organism.

Question 26Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A whole blood unit is collected into a bag containing CP2D and then processed into components. What is the maximum storage period for the red blood cells when an additive solution is not added?

  1. 42 days at 1 to 6 °C
  2. 24 hours at 20 to 24 °C
  3. 21 days at 1 to 6 °C Correct answer.
  4. 35 days at 1 to 6 °C

Explanation

Red cells collected in CP2D and stored without an additive solution have a maximum shelf life of 21 days at 1 to 6 °C. Adding an additive solution extends storage to 42 days, and storage at 20 to 24 °C is not acceptable for red cells.

Question 27Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor's arm is prepared with an iodophor scrub before phlebotomy. Which step is required to ensure the antiseptic does not contaminate the collection?

  1. Rinse the site with sterile saline before needle insertion
  2. Apply a second iodophor scrub and insert the needle while still wet
  3. Wipe the site with 70% isopropyl alcohol immediately after scrubbing
  4. Allow the iodophor to dry completely before venipuncture Correct answer.

Explanation

The skin antiseptic must be allowed to dry on the skin to achieve maximal antimicrobial effect and to avoid introducing residual antiseptic into the collection. Inserting the needle while the site is wet can contaminate the unit and cause hemolysis.

Question 28Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A donor completes a whole blood donation, and the unit is intended for production of platelets. Which handling step is essential to preserve platelet function?

  1. Refrigerate the whole blood immediately at 1 to 6 °C until processing
  2. Maintain the whole blood at 20 to 24 °C and process it within 8 hours of collection Correct answer.
  3. Hold the whole blood at 37 °C until the laboratory is ready to centrifuge
  4. Freeze the whole blood at −18 °C within 4 hours of collection

Explanation

When platelets are to be recovered, whole blood is kept at 20 to 24 °C and processed within 8 hours of collection, because cold exposure and delay impair platelet viability and function. Refrigeration is appropriate only when red cells or plasma are the desired products.

Question 29Whole Blood and Blood Components: donor eligibility, collection, processing, labeling, storage, indications for use

A hospital requests whole blood for a patient with massive hemorrhage. The inventory whole blood units were collected in CPD and stored at 1 to 6 °C. Which statement best describes the functional limitation of these units compared with red cell concentrates?

  1. They have a higher hematocrit than red cell concentrates and must be diluted before use
  2. They lack any anticoagulant and will clot in the bag
  3. They cannot be used in patients with active bleeding because they contain no plasma
  4. They contain labile clotting factors that are largely nonfunctional after storage beyond 24 hours Correct answer.

Explanation

Whole blood retains plasma, but the labile factors V and VIII deteriorate during refrigerated storage, so whole blood stored beyond about 24 hours does not provide functional labile coagulation factors. This is why component therapy with red cells, plasma, and platelets is used for massive transfusion.

Question 30Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which ABO genotype is associated with the A2 subgroup phenotype?

  1. A1A1
  2. AA Correct answer.
  3. AO
  4. A1O

Explanation

The A2 phenotype arises from an A allele that produces a less efficient glycosyltransferase, typically the A2 allele. In genotype notation, A2A2 or A2O would be written, but among the choices AA represents the A2 allele pairing that yields the A2 subgroup when the second allele is also A2 or O. A1 alleles produce the A1 phenotype.

Question 31Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient's serum agglutinates reagent A1 cells but not reagent A2 cells or B cells. What is the most likely explanation?

  1. The patient is group O
  2. The patient is group AB
  3. The patient is group A2 with anti-A1 Correct answer.
  4. The patient is group B with anti-A1

Explanation

Anti-A1 reacts with A1 cells but not with A2 cells, and it does not react with B cells. This pattern is characteristic of a group A2 (or A2B) individual who has produced anti-A1. Group B serum would react with both A1 and A2 cells.

Question 32Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which blood group system antigens are carried on the band 3 protein of the red cell membrane?

  1. Lutheran
  2. Diego Correct answer.
  3. Kell
  4. Duffy

Explanation

Diego antigens (Di-a and Di-b) reside on band 3, the anion exchanger protein. Kell is on a glycoprotein of the Kell system, Lutheran on the Lutheran glycoprotein, and Duffy on the Duffy chemokine receptor.

Question 33Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient with sickle cell disease requires transfusion. Which antigen phenotype is most important to match to prevent alloimmunization and delayed hemolytic reactions in this population?

  1. Lewis
  2. C, E, and Kell Correct answer.
  3. P1
  4. Kidd

Explanation

Extended matching for Rh (C, E) and Kell antigens is recommended for patients with sickle cell disease because alloimmunization to these antigens is common and clinically significant in this population. Lewis and P1 antibodies are typically cold-reactive and not the primary concern.

Question 34Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

What is the principle of the indirect antiglobulin test (IAT)?

  1. It detects IgM antibodies only
  2. It detects antibodies that bind red cells in vitro after incubation Correct answer.
  3. It detects antibodies already bound to red cells in vivo
  4. It measures complement fixation on the red cell surface

Explanation

The IAT detects antibodies that bind to red cells during in vitro incubation; unbound antibody is washed away and bound antibody is detected with anti-human globulin. The direct antiglobulin test detects antibody already bound in vivo.

Question 35Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient's serum reacts with all reagent screening cells at the IAT phase, and the autocontrol is negative. What is the most appropriate next step?

  1. Report the antibody as an autoantibody
  2. Transfuse group O blood without further testing
  3. Test an extended panel of reagent cells to identify the antibody Correct answer.
  4. Perform a direct antiglobulin test only

Explanation

A panreactive serum with a negative autocontrol suggests an alloantibody directed against a high-incidence antigen or multiple antibodies. Testing an extended panel (and possibly rare cells) is needed to identify the specificity.

Question 36Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which antibody is most commonly associated with delayed hemolytic transfusion reactions?

  1. anti-Jka Correct answer.
  2. anti-P1
  3. anti-Lea
  4. Anti-I

Explanation

Kidd system antibodies, especially anti-Jka, often fall to undetectable levels and are a classic cause of delayed hemolytic transfusion reactions. Anti-I, anti-Lea, and anti-P1 are typically cold-reactive and clinically insignificant.

Question 37Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

What is the purpose of the immediate spin phase in a crossmatch?

  1. To detect IgG antibodies
  2. To detect complement-binding antibodies
  3. To detect warm autoantibodies
  4. To detect ABO incompatibility Correct answer.

Explanation

The immediate spin phase primarily detects IgM antibodies, most importantly anti-A and anti-B, and thus identifies ABO incompatibility. IgG and warm antibodies are detected at the antiglobulin phase.

Question 38Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient is group B and has anti-A1 in addition to anti-A. Which red cells are compatible for transfusion?

  1. Group A2 cells
  2. Group O cells
  3. Group B cells Correct answer.
  4. Group A1 cells

Explanation

A group B patient can safely receive group B red cells, which lack A antigens. Group A1 and A2 cells carry A antigens that react with anti-A, and group O cells carry H antigen but are not the patient's own type; the compatible choice among the options is group B.

Question 39Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which of the following is a characteristic of the RhD antigen?

  1. It is absent from cord blood
  2. It is encoded by the RHD gene Correct answer.
  3. It is present on the red cell membrane as a lipid-linked structure
  4. It requires complement for expression

Explanation

The RhD antigen is encoded by the RHD gene and is a protein-based antigen in the Rh system. It is not lipid-linked and does not require complement for expression.

Question 40Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient with a history of anti-Jka needs transfusion. Which crossmatch approach is most appropriate?

  1. Immediate spin crossmatch only
  2. Antiglobulin crossmatch with Jka-negative units Correct answer.
  3. Electronic crossmatch
  4. Saline crossmatch

Explanation

When a clinically significant antibody such as anti-Jka is present, units should be antigen-negative and an antiglobulin crossmatch should be performed. Immediate spin or electronic crossmatch alone is insufficient.

Question 41Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

What is the significance of a positive direct antiglobulin test in a patient with anemia?

  1. It indicates the presence of free antibody in serum
  2. It indicates a cold agglutinin only
  3. It indicates ABO incompatibility only
  4. It indicates the presence of bound antibody or complement on red cells Correct answer.

Explanation

A positive DAT demonstrates that antibody and/or complement is bound to the patient's red cells in vivo, which supports an immune hemolytic process. It does not detect free serum antibody or define ABO incompatibility.

Question 42Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient's serum reacts with all reagent cells except those lacking the Vel antigen. What antibody is most likely present?

  1. anti-Vel Correct answer.
  2. anti-Lan
  3. anti-Jra
  4. anti-Kpa

Explanation

Anti-Vel reacts with Vel-positive cells and fails to react with Vel-negative cells. It is a high-incidence antibody that can cause hemolytic transfusion reactions.

Question 43Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which of the following best describes the function of polyethylene glycol (PEG) in antibody detection testing?

  1. It enhances antigen-antibody reactions by increasing the dielectric constant Correct answer.
  2. It lyses red cells
  3. It neutralizes IgM antibodies
  4. It inhibits complement activation

Explanation

PEG enhances antigen-antibody reactions by increasing the dielectric constant and removing water from the red cell surface, promoting antibody binding. It does not lyse cells or neutralize antibodies.

Question 44Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient with a cold agglutinin of high titer requires transfusion. Which approach is most appropriate?

  1. Use group O blood only
  2. Transfuse through a blood warmer and use a prewarmed crossmatch Correct answer.
  3. Perform an electronic crossmatch
  4. Transfuse at room temperature

Explanation

For clinically significant cold agglutinins, transfusing through a blood warmer and performing a prewarmed crossmatch helps prevent in vitro hemolysis. Room temperature transfusion and electronic crossmatch are not appropriate.

Question 45Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which antigen is part of the MNS blood group system?

  1. Jka
  2. Fya
  3. S Correct answer.
  4. Lea

Explanation

The S antigen is part of the MNS system along with M, N, and s. Fya is Duffy, Jka is Kidd, and Lea is Lewis.

Question 46Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

What is the most likely cause of a discrepancy between forward and reverse ABO typing in a patient with a recent bone marrow transplant?

  1. Loss of ABO antigens on donor red cells
  2. Anti-A1 in group A2
  3. Chimerism with mixed red cell populations Correct answer.
  4. Acquired B antigen

Explanation

After bone marrow transplant, chimerism can produce mixed red cell populations, causing discrepancies between forward and reverse typing. Acquired B and anti-A1 are unrelated to transplant chimerism.

Question 47Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

Which of the following is a clinically significant antibody of the Duffy system?

  1. anti-Fya Correct answer.
  2. anti-I
  3. anti-P1
  4. anti-Lea

Explanation

Anti-Fya is a clinically significant Duffy antibody that can cause hemolytic transfusion reactions and HDFN. Anti-Lea, anti-P1, and anti-I are typically clinically insignificant cold-reactive antibodies.

Question 48Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient has an antibody that reacts only with enzyme-treated cells. Which antibody is most likely?

  1. anti-Jka Correct answer.
  2. anti-D
  3. anti-M
  4. anti-Fya

Explanation

Kidd antibodies such as anti-Jka often show enhanced reactivity with enzyme-treated cells. Anti-M and anti-Fya may show reduced reactivity with enzymes, and anti-D is not specifically enzyme-dependent.

Question 49Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

What is the primary purpose of performing an antibody screen before transfusion?

  1. To measure hemoglobin levels
  2. To detect clinically significant antibodies in the patient's serum Correct answer.
  3. To assess platelet function
  4. To determine the patient's ABO type

Explanation

The antibody screen detects clinically significant antibodies in the patient's serum that could cause hemolytic transfusion reactions. ABO typing is performed separately, and hemoglobin and platelet function are unrelated.

Question 50Immunohematology and Genetics: blood groups, antigen/antibody detection and identification, compatibility testing, blood product selection

A patient with anti-K and anti-Jka requires surgery. Which units should be selected?

  1. K-negative, Jka-positive units
  2. K-positive, Jka-negative units
  3. K-positive, Jka-positive units
  4. K-negative, Jka-negative units Correct answer.

Explanation

Units must be negative for all clinically significant antigens to which the patient has antibodies. Therefore K-negative and Jka-negative units are required to prevent hemolytic reactions.