Compatibility Testing Flashcards

*Question: What is the maximum acceptable age of a blood specimen for pretransfusion testing?
A) 24 hours
B) 48 hours
C) 72 hours
D) 96 hours

*Answer: C) 72 hours

*Question: Which tube is the preferred specimen for blood bank testing?
A) Red top
B) Lavender top
C) Pink top (EDTA)
D) Green top (heparin)

*Answer: C) Pink top (EDTA)

*Question: When drawing blood from an IV line, how much blood must be discarded first?
A) 5 mL
B) 10 mL
C) 15 mL
D) 20 mL

*Answer: B) 10 mL

*Question: How long before drawing from an IV line should the IV be stopped?
A) 2–3 minutes
B) 5–10 minutes
C) 15–20 minutes
D) 30 minutes

*Answer: B) 5–10 minutes

*Question: Where must blood specimen labels be placed?
A) At the nursing station before collection
B) In the blood bank upon arrival
C) At the bedside during collection
D) By the phlebotomist before going to the patient

*Answer: C) At the bedside during collection

*Question: Which of the following is detected in the IS phase of the crossmatch?
A) IgG antibodies
B) Complement-dependent IgG
C) IgM cold-reacting antibodies
D) Rh antibodies

*Answer: C) IgM cold-reacting antibodies

*Question: Which phase of the crossmatch detects antibodies of the Rh, Duffy, and Kidd systems?
A) IS phase
B) 37°C phase
C) AHG phase
D) OCC phase

*Answer: C) AHG phase

*Question: What is the purpose of the One Cell Check (OCC) phase?
A) To detect IgM antibodies
B) To detect ABO incompatibility
C) To validate that AHG reagent is still active
D) To confirm the donor's blood type

*Answer: C) To validate that AHG reagent is still active

*Question: What result must the OCC phase always show?
A) Negative
B) 1+ agglutination
C) Positive
D) Hemolysis

*Answer: C) Positive

*Question: The major crossmatch uses which combination?
A) Donor serum + patient RBCs
B) Patient serum + patient RBCs
C) Patient serum + donor RBCs
D) Donor serum + donor RBCs

*Answer: C) Patient serum + donor RBCs

*Question: The minor crossmatch was discontinued by AABB in what year?
A) 1968
B) 1972
C) 1976
D) 1980

*Answer: C) 1976

*Question: Why was the minor crossmatch discontinued?
A) It was too expensive
B) Donor plasma antibodies are diluted to insignificant levels in PRBC units
C) It caused more transfusion reactions
D) It required too much patient serum

*Answer: B) Donor plasma antibodies are diluted to insignificant levels in PRBC units

*Question: Abbreviated crossmatch has been allowed since which decade?
A) 1960s
B) 1970s
C) 1980s
D) 1990s

*Answer: C) 1980s

*Question: Which condition must be met to perform an abbreviated (incomplete) crossmatch?
A) Patient has never been transfused
B) Patient has no history of alloantibodies AND current antibody screen is negative
C) Patient is under 18 years old
D) Patient has a negative DAT

*Answer: B) Patient has no history of alloantibodies AND current antibody screen is negative

*Question: Which blood group is the universal RBC donor?
A) A
B) B
C) AB
D) O

*Answer: D) O

*Question: Which blood group is the universal plasma donor?
A) O
B) A
C) B
D) AB

*Answer: D) AB

*Question: Which blood group is the universal RBC recipient?
A) O
B) A
C) B
D) AB

*Answer: D) AB

*Question: What is the first alternative RBC unit for a Group A patient?
A) B
B) AB
C) O
D) A negative only

*Answer: C) O

*Question: Which blood type has NO alternative RBC donor group?
A) A
B) B
C) O
D) AB

*Answer: C) O

*Question: What emergency blood product is given to women of childbearing age when blood type is unknown?
A) O Rh-positive PRBCs
B) O Rh-negative PRBCs
C) AB Rh-negative PRBCs
D) A Rh-negative PRBCs

*Answer: B) O Rh-negative PRBCs

*Question: What plasma type is considered the universal plasma product?
A) O plasma
B) A plasma
C) B plasma
D) AB plasma

*Answer: D) AB plasma

*Question: What is massive transfusion defined as?
A) Transfusing 5 units within 12 hours
B) Transfusing ≥ total blood volume (5L or 10–12 units) within 24 hours
C) Transfusing 3 units of whole blood in 6 hours
D) Transfusing ≥ 8 units of FFP within 48 hours

*Answer: B) Transfusing ≥ total blood volume (5L or 10–12 units) within 24 hours

*Question: In a massive transfusion scenario with no prior antibodies, what units should be given?
A) O-negative units only
B) Antigen-negative units
C) ABO-identical units
D) AB units only

*Answer: C) ABO-identical units

*Question: If antibodies were previously identified in a massively transfused patient, what should be given?
A) O-negative units regardless
B) ABO-identical units
C) Antigen-negative units for the identified antibody
D) Crossmatch-incompatible units are acceptable

*Answer: C) Antigen-negative units for the identified antibody

*Question: For how long are donor segments retained after a unit's expiration for crossmatching purposes?
A) 7 days
B) 14 days
C) 30 days
D) 49 days

*Answer: D) 49 days

*Question: What must be stated on the tag of uncrossmatched emergency blood?
A) "Emergency use only"
B) "Not crossmatched"
C) "Incompatible unit"
D) "Universal donor"

*Answer: B) "Not crossmatched"

*Question: Who must sign the release form for emergency uncrossmatched blood?
A) The charge nurse
B) The blood bank technologist
C) The physician
D) The hospital administrator

*Answer: C) The physician

*Question: Which of the following is NOT a function of the crossmatch?
A) Verify ABO compatibility
B) Detect most clinically significant antibodies
C) Guarantee RBC survival
D) Double-check ABO errors

*Answer: C) Guarantee RBC survival

*Question: Which of the following CANNOT be detected by the crossmatch?
A) ABO incompatibility
B) Most IgG antibodies
C) Non-hemolytic febrile reactions
D) Most clinically significant alloantibodies

*Answer: C) Non-hemolytic febrile reactions

*Question: An antibody screen is positive but the crossmatch is negative. What is the most likely explanation?
A) The antibody reacts with donor RBC antigens
B) The antibody reacts with antigens on the screening cell only
C) There is ABO incompatibility
D) The patient has a positive DAT

*Answer: B) The antibody reacts with antigens on the screening cell only

*Question: An antibody screen is negative but the crossmatch is positive. What should be done first?
A) Issue the unit immediately
B) Perform DAT on donor unit or identify the antibody
C) Repeat the ABO typing
D) Discard the donor unit

*Answer: B) Perform DAT on donor unit or identify the antibody

*Question: The gel technology crossmatch incubates at what temperature and for how long?
A) Room temperature for 5 minutes
B) 37°C for 15 minutes
C) 4°C for 30 minutes
D) 37°C for 30 minutes

*Answer: B) 37°C for 15 minutes

*Question: Gel technology cannot detect which class of antibody?
A) IgG
B) IgA
C) IgM
D) IgE

*Answer: C) IgM

*Question: Why is gel technology's inability to detect IgM clinically acceptable?
A) IgM antibodies are too large to cause reactions
B) Clinically significant antibodies are predominantly IgG
C) IgM is detected by other methods automatically
D) IgM does not exist in blood bank testing

*Answer: B) Clinically significant antibodies are predominantly IgG

*Question: In gel technology, what does it mean when cells are trapped at the top of the gel column?
A) The sample is compatible
B) The sample is inconclusive
C) The sample is incompatible (agglutination occurred)
D) The test must be repeated

*Answer: C) The sample is incompatible (agglutination occurred)

*Question: In gel technology, what does it mean when cells pellet to the bottom of the gel column?
A) Incompatible
B) Inconclusive
C) Compatible (no agglutination)
D) Requires further testing

*Answer: C) Compatible (no agglutination)

*Question: What RBC concentration is used in gel technology?
A) 3%
B) 5%
C) 1%
D) 0.5%

*Answer: C) 1%

*Question: Which of the following is a requirement for electronic/computer crossmatch per AABB?
A) Patient must have been previously transfused
B) Patient ABO/Rh must be entered once
C) No current OR historical clinically significant alloantibodies
D) Patient age must be over 18

*Answer: C) No current OR historical clinically significant alloantibodies

*Question: How many times must patient ABO/Rh be entered in computer crossmatch?
A) Once
B) Twice
C) Three times
D) As confirmed by the physician

*Answer: B) Twice

*Question: Which specimens require ABO/Rh double-checking?
A) All blood components
B) FFP and platelets only
C) RBC-containing units only (whole blood, PRBCs)
D) Cryoprecipitate and granulocytes

*Answer: C) RBC-containing units only (whole blood, PRBCs)

*Question: Which components do NOT require a double check of ABO/Rh typing?
A) Whole blood
B) PRBCs
C) FFP, platelets, cryoprecipitate
D) Washed RBCs

*Answer: C) FFP, platelets, cryoprecipitate

*Question: What is BECS in the context of compatibility testing?
A) Blood Exchange and Crossmatch System
B) Blood Establishment Computer System — tracks personnel and procedures
C) Biological Emergency Control Standard
D) Blood Electrolyte and Chemistry Screen

*Answer: B) Blood Establishment Computer System — tracks personnel and procedures

*Question: True hemolysis in a patient specimen indicates what?
A) Faulty centrifugation
B) Complement activation
C) Rouleaux formation
D) Sample is too old

*Answer: B) Complement activation

*Question: A hemolyzed specimen from venipuncture should be:
A) Accepted and tested normally
B) Diluted before testing
C) Possibly rejected
D) Centrifuged again

*Answer: C) Possibly rejected

*Question: Which of the following antibodies is typically detected in the IS phase and is clinically insignificant?
A) Anti-D
B) Anti-K
C) Anti-Lea
D) Anti-Jka

*Answer: C) Anti-Lea

*Question: Which system's antibodies are detected in the AHG phase and are clinically significant?
A) Lewis system
B) MN system
C) Kidd system
D) P1PK system

*Answer: C) Kidd system

*Question: Which antibody class is warm-reacting and detected at 37°C?
A) IgM
B) IgD
C) IgG
D) IgE

*Answer: C) IgG

*Question: What temperature does the 37°C/LISS phase specifically detect?
A) Cold-reacting IgM antibodies
B) Potent IgG Rh antibodies
C) IgM complement-fixing antibodies
D) IgA antibodies

*Answer: B) Potent IgG Rh antibodies

*Question: If a patient has a previously identified alloantibody, what must be done even during emergencies?
A) Skip crossmatch entirely
B) Give O-negative blood automatically
C) Provide antigen-negative units and perform IS + AHG crossmatch
D) Transfuse ABO-identical units without further testing

*Answer: C) Provide antigen-negative units and perform IS + AHG crossmatch

*Question: Who authorizes the release of uncrossmatched units during an emergency?
A) Charge nurse
B) Hospital administrator
C) Blood bank head/medical director
D) Senior phlebotomist

*Answer: C) Blood bank head/medical director

*Question: What is the acceptable temperature range for returning unused RBC units?
A) 0°C to 4°C
B) 1°C to 6°C
C) 1°C to 10°C
D) 2°C to 8°C

*Answer: C) 1°C to 10°C

*Question: A returned blood unit must be brought back within how many minutes if temperature was not maintained?
A) 15 minutes
B) 20 minutes
C) 30 minutes
D) 60 minutes

*Answer: C) 30 minutes

*Question: What must remain intact for a blood unit to be accepted back into inventory?
A) The donor tag
B) The unit closure (must be unopened)
C) The compatibility label
D) The pilot tube

*Answer: B) The unit closure (must be unopened)

*Question: Which of the following must be compared when issuing blood to a patient?
A) Requisition form + donor unit tag + blood product label
B) Physician's order + patient wristband + blood type card
C) Nurse's notes + blood bank log + compatibility form
D) Donor history + patient history + antibody screen results

*Answer: A) Requisition form + donor unit tag + blood product label

*Question: Which component is used from the donor unit for crossmatching?
A) Main bag supernatant
B) Attached segments
C) Pilot tube
D) Satellite bag

*Answer: B) Attached segments

*Question: What tool is used to cut donor segments while maintaining the closed system?
A) Standard scissors
B) Scalpel
C) Dielectric tube sealer
D) Heat sealer clamp

*Answer: C) Dielectric tube sealer

*Question: Neonates under what age are assumed to have only maternally-derived antibodies?
A) 1 month
B) 2 months
C) 3 months
D) 4 months

*Answer: D) 4 months

*Question: What are pedipacks?
A) Special needles for neonatal phlebotomy
B) Small-volume blood aliquots prepared for infant transfusion
C) Pediatric crossmatch reagents
D) Neonatal-safe IV tubing

*Answer: B) Small-volume blood aliquots prepared for infant transfusion

*Question: Which of the following serum can be used for neonatal crossmatching?
A) Infant serum only
B) Maternal serum only
C) Either infant or maternal serum
D) Neither — only direct typing is used

*Answer: C) Either infant or maternal serum

*Question: Which components do NOT require crossmatching but should still be ABO compatible?
A) Whole blood and PRBCs
B) Washed RBCs and irradiated RBCs
C) FFP, platelets, cryoprecipitate
D) Granulocytes and leukoreduced RBCs

*Answer: C) FFP, platelets, cryoprecipitate

*Question: What is the Type and Screen procedure used for?
A) Full pretransfusion workup for all patients
B) Conserving blood inventory; only IS phase crossmatch needed if screen is negative
C) Emergency releases only
D) Neonatal transfusions

*Answer: B) Conserving blood inventory; only IS phase crossmatch needed if screen is negative

*Question: Which of the following is a limitation of pretransfusion compatibility testing?
A) It cannot detect ABO incompatibility
B) It can only detect IgM antibodies
C) Weak antibodies below detection threshold can still cause hemolytic reactions
D) It always guarantees RBC survival

*Answer: C) Weak antibodies below detection threshold can still cause hemolytic reactions

*Question: How many antibody molecules per RBC are typically needed for a detectable IAT reaction?
A) Tens
B) Hundreds
C) Thousands
D) Millions

*Answer: B) Hundreds

*Question: What is the first step when an incompatible crossmatch result is due to suspected ABO incompatibility?
A) Call the physician immediately
B) Perform a DAT on the donor unit
C) Recheck ABO typing of both patient and donor unit
D) Discard the unit

*Answer: C) Recheck ABO typing of both patient and donor unit

*Question: When an incompatible crossmatch suggests a clinically significant antibody, what two tests should be done?
A) DAT and LAT (Leukocyte Antibody Test)
B) DAT on donor and antibody identification
C) ABO recheck and Rh control repeat
D) Elution and adsorption

*Answer: B) DAT on donor and antibody identification

*Question: Crossmatch must still be performed retroactively even when emergency blood was issued. True or false — and what is the reason?
A) False — no crossmatch needed after transfusion
B) True — to prevent or help manage transfusion reactions
C) True — only to satisfy legal requirements
D) False — retroactive crossmatch is never performed

*Answer: B) True — to prevent or help manage transfusion reactions

*Question: In which phase of pretransfusion testing is the Rh control checked?
A) Antibody screen
B) Crossmatch IS phase
C) ABO/Rh typing
D) OCC phase

*Answer: C) ABO/Rh typing

*Question: If the Rh control is positive, what does this mean?
A) Patient is Rh positive
B) Patient is Rh negative
C) Result is invalid — test must be repeated
D) Rh typing is confirmed

*Answer: C) Result is invalid — test must be repeated

*Question: Forward and reverse ABO typing results that do NOT match indicate what?
A) Normal variation
B) Patient is Group O
C) ABO discrepancy — requires investigation
D) Sample is too old

*Answer: C) ABO discrepancy — requires investigation

*Question: Which of the following is a pre-analytical error that can lead to a transfusion reaction?
A) Positive OCC
B) Negative antibody screen
C) Patient misidentification
D) ABO/Rh double-check

*Answer: C) Patient misidentification

*Question: A 5% red cell suspension (RCS) cannot be prepared from which tube?
A) Pink top (EDTA)
B) Lavender top (EDTA)
C) Red top (clotted blood)
D) Yellow top (ACD)

*Answer: C) Red top (clotted blood)

*Question: Which of the following is a reason a specimen may be REJECTED in the blood bank?
A) Sample drawn from antecubital vein
B) Sample is hemolyzed from venipuncture error
C) Sample arrived within 72 hours
D) Sample was labeled with patient's full name

*Answer: B) Sample is hemolyzed from venipuncture error

*Question: In the Philippine blood bank setting, which procedures are typically performed due to resource limitations?
A) ABO/Rh typing and antibody screen only
B) ABO/Rh typing and crossmatch only
C) Antibody screen and crossmatch only
D) Full 3-phase crossmatch with antibody identification

*Answer: B) ABO/Rh typing and crossmatch only

*Question: What information must be on the compatibility label issued with the blood unit?
A) Patient's diet and allergies
B) Patient name, ID, ABO/Rh of patient and unit, donor #, XM results, tech ID
C) Nurse's name and patient's weight
D) Physician's license number and blood bank address

*Answer: B) Patient name, ID, ABO/Rh of patient and unit, donor #, XM results, tech ID

*Question: What is the function of LISS in the 37°C phase of crossmatching?
A) Enhances detection of IgM antibodies
B) Reduces ionic strength to potentiate IgG antibody detection
C) Inactivates complement
D) Preserves RBC antigens

*Answer: B) Reduces ionic strength to potentiate IgG antibody detection

*Question: An autologous transfusion refers to:
A) Transfusion between identical twins
B) A patient donating blood for their own future use
C) Transfusion of O-negative blood to any patient
D) Emergency transfusion without crossmatch

*Answer: B) A patient donating blood for their own future use

*Question: Which statement about antibody screen vs crossmatch is MOST accurate?
A) Antibody screen replaces the crossmatch entirely
B) Antibody screen detects unexpected antibodies in patient serum using reagent screening cells
C) Antibody screen uses donor cells directly
D) Crossmatch detects all possible antibodies

*Answer: B) Antibody screen detects unexpected antibodies in patient serum using reagent screening cells

*Question: Anti-D, anti-K, and anti-Jka are examples of which type of antibodies?
A) Naturally occurring, clinically insignificant
B) Cold-reacting IgM antibodies
C) Clinically significant IgG alloantibodies
D) Autoantibodies

*Answer: C) Clinically significant IgG alloantibodies

*Question: Anti-M, anti-N, anti-Lea, and anti-I are typically detected in which phase?
A) AHG
B) 37°C
C) IS
D) OCC

*Answer: C) IS

*Question: If the antibody screen detects an unexpected antibody, what is the NEXT step?
A) Immediately discard all donor units
B) Issue O-negative blood
C) Identify the antibody using panel cells and autocontrol
D) Repeat the crossmatch using gel technology

*Answer: C) Identify the antibody using panel cells and autocontrol

*Question: What reagent is added in the AHG phase to detect IgG sensitization?
A) Low Ionic Strength Solution
B) Anti-Human Globulin (Coombs reagent)
C) Saline
D) Albumin

*Answer: B) Anti-Human Globulin (Coombs reagent)

*Question: A complete crossmatch includes which phases?
A) IS only
B) IS + AHG
C) IS + 37°C + AHG
D) 37°C + AHG only

*Answer: C) IS + 37°C + AHG

*Question: Which of the following is NOT included in the specimen label?
A) Patient's full name
B) Hospital number
C) Patient's diagnosis
D) Date and time of collection

*Answer: C) Patient's diagnosis

*Question: What must the nurse do before administering a transfusion?
A) Draw a new specimen for repeat crossmatch
B) Listen for the technologist's verbal confirmation
C) Read the blood product label in front of a watcher and confirm details
D) Administer a pre-medication without checking labels

*Answer: C) Read the blood product label in front of a watcher and confirm details

*Question: Donor blood bags are stored in what position, and how do RBCs settle?
A) Inverted; RBCs rise to top
B) Upright; RBCs settle to bottom with plasma on top
C) Horizontal; uniform mixing occurs
D) Upright; plasma settles to bottom

*Answer: B) Upright; RBCs settle to bottom with plasma on top

*Question: Which of the following CANNOT be prevented by compatibility testing?
A) Hemolytic transfusion reactions due to ABO incompatibility
B) Detection of most IgG antibodies
C) Delayed transfusion reactions caused by anamnestic responses
D) Verification of ABO errors

*Answer: C) Delayed transfusion reactions caused by anamnestic responses

*Question: The AABB standard states the crossmatch shall include which mandatory phase?
A) IS phase only
B) 37°C phase only
C) An antiglobulin (AHG) phase
D) Electronic phase only

*Answer: C) An antiglobulin (AHG) phase

*Question: Which of the following donor records must be entered into the computer for electronic crossmatch?
A) Donor's name and birthdate
B) Donor unit ID, ABO/Rh, component name
C) Donor's antibody history
D) Donor's transfusion history

*Answer: B) Donor unit ID, ABO/Rh, component name

*Question: Which is the correct order of pretransfusion serological testing?
A) Antibody screen → ABO/Rh → Crossmatch
B) Crossmatch → ABO/Rh → Antibody screen
C) ABO/Rh typing → Antibody screen → Crossmatch
D) Crossmatch → Antibody screen → ABO/Rh

*Answer: C) ABO/Rh typing → Antibody screen → Crossmatch

*Question: Which statement correctly describes the solid phase adherence assay (SPAA)?
A) It uses gel columns to trap agglutinated cells
B) It uses a solid surface to bind antigens or antibodies for detection
C) It detects only IgM antibodies
D) It is used exclusively for neonatal testing

*Answer: B) It uses a solid surface to bind antigens or antibodies for detection

*Question: A blood unit can be reissued after return to the blood bank ONLY IF which condition is confirmed?
A) The nurse signed the return form
B) The unit is unopened AND temperature was maintained between 1°C–10°C
C) The crossmatch was negative
D) The expiration date has not yet passed

*Answer: B) The unit is unopened AND temperature was maintained between 1°C–10°C

*Question: Which of the following is the correct action when a patient with a known alloantibody requires blood during an emergency?
A) Transfuse O-negative without crossmatch and do nothing further
B) Skip antigen typing and give ABO-identical units
C) Release antigen-negative units; perform IS + AHG crossmatch; get blood bank head approval
D) Use electronic crossmatch only

*Answer: C) Release antigen-negative units; perform IS + AHG crossmatch; get blood bank head approval