Compatibility Testing

Question 1

1. SITUATION: An emergency trauma patient requires transfusion. Six units of blood are ordered stat. There is no time to draw a patient sample. O-negative blood is released. When will compatibility testing be performed?

A. Compatibility testing must be performed before blood is issued
B. Compatibility testing will be performed when a patient sample is available
C. Compatibility testing may be performed
immediately using donor serum
D. Compatibility testing is not necessary when blood is released in emergency situations

Answer 1

b

Question 2

2. How would autoantibodies affect compatibility testing?
   A. No effect
   B. The DAT would be positive
   C. ABO, Rh, antibody screen, and crossmatch may show abnormal results
   D. Results would depend on the specificity of
   autoantibody

Answer 2

c

Question 3

3. An antibody screen is reactive at IAT phase of testing using a three-cell screen and the autocontrol is negative. What is a possible explanation for these results?

A. A cold alloantibody
B. High-frequency alloantibody or a mixture of alloantibodies
C. A warm autoantibody
D. A cold and warm alloantibody

Answer 3

b

Question 4

4. What does a minor crossmatch consist of?
   A. Recipient plasma and recipient red cells
   B. Recipient plasma and donor red cells
   C. Recipient red cells and donor plasma
   D. Donor plasma and donor red cells

Answer 4

c

Question 5

5. Can crossmatching be performed on October 14th using a patient sample drawn on October 12th?
   A. Yes, a new sample would not be needed
   B. Yes, but only if the previous sample has no alloantibodies
   C. No, a new sample is needed because the 2-day limit has expired
   D. No, a new sample is needed for each testing

Answer 5

a

Question 6

6. A type and screen was performed on a 32-year-old woman, and the patient was typed as AB negative. There are no AB-negative units in the blood bank.
   What should be done?

A. Order AB-negative units from a blood supplier
B. Check inventory of A-, B-, and O-negative units
C. Ask the patient to make a preoperative
autologous donation
D. Nothing—the blood will probably not be used

Answer 6

b

Question 7

7. What ABO types may donate to any other
   ABO type?

A. A negative, B negative, AB negative, O negative
B. O negative
C. AB negative
D. AB negative, A negative, B negative

Answer 7

b

Question 8

9. A technologist removed 4 units of blood from the blood bank refrigerator and placed them on the counter. A clerk was waiting to take the units for transfusion. As she checked the paperwork, she
   noticed that one of the units was leaking onto the counter. What should she do?
   A. Issue the unit if the red cells appear normal
   B. Reseal the unit
   C. Discard the unit
   D. Call the medical director and ask for an opinion

Answer 8

c

Question 9

10. A donor was found to contain anti-K using pilot tubes from the collection procedure. How would this affect the compatibility test?

A. The AHG major crossmatch would be positive
B. The IS (immediate spin) major crossmatch would be positive
C. The recipient’s antibody screen would be positive for anti-K
D. Compatibility testing would not be affected

Answer 9

d

Question 10

11. Which of the following is not a requirement for the electronic crossmatch?

A. The computer system contains logic to prevent assignment and release of ABO incompatible blood
B. There are concordant results of at least two determinations of the recipient’s ABO type on record, one of which is from the current sample
C. Critical elements of the system have been validated on site
D. There are concordant results of at least one determination of the recipient’s ABO type on file

Answer 10

d

Question 11

12. A patient showed positive results with screening cells and 4 donor units. The patient autocontrol was negative. What is the most likely antibody?

A. Anti-H
B. Anti-S
C. Anti-Kpa
D. Anti-k

Answer 11

d

Question 12

13. Screening cells and major crossmatch are positive on IS only, and the autocontrol is negative. Identify the problem.
A. Cold alloantibody
B. Cold autoantibody
C. Abnormal protein
D. Antibody mixture

Answer 12

a

Question 13

14. Six units are crossmatched. Five units are
    compatible, one unit is incompatible, and the
    recipient’s antibody screen is negative. Identify the problem:

A. Patient may have an alloantibody to a
high-frequency antigen
B. Patient may have an abnormal protein
C. Donor unit may have a positive DAT
D. Donor may have a high-frequency antigen

Answer 13

c

Question 14

15. An incompatible donor unit is found to have a positive DAT. What should be done with the donor unit?
    A. Discard the unit
    B. Antigen type the unit for high-frequency
    antigens
    C. Wash the donor cells and use the washed cells for testing
    D. Perform a panel on the incompatible unit

Answer 14

a

Question 15

16. Screening cells, major crossmatch, and patient autocontrol are positive in all phases. Identify the problem.

A. Specific cold alloantibody
B. Specific cold autoantibody
C. Abnormal protein or nonspecific autoantibody
D. Cold and warm alloantibody mixture

Answer 15

c

Question 16

17. A panel study has revealed the presence of patient alloantibodies. What is the first step in a major crossmatch?

A. Perform a DAT on patient cells and donor units
B. Antigen type patient cells and any donor cells to be crossmatched
C. Adsorb any antibodies from the patient serum
D. Obtain a different enhancement medium for testing

Answer 16

b

Question 17

18. What is the disposition of a donor red blood cell unit that contains an antibody?

A. The unit must be discarded
B. Only the plasma may be used to make
components
C. The antibody must be adsorbed from the unit
D. The unit may be labeled indicating it contains antibody and released into inventory

Answer 17

d

Question 18

19. Given a situation where screening cells, major crossmatch, autocontrol, and DAT (anti-IgG) are all positive, what procedure should be performed next?
    A. Adsorption using rabbit stroma
    B. Antigen typing of patient cells
    C. Elution followed by a cell panel on the eluate
    D. Selected cell panel

Answer 18

c

Question 19

20. A major crossmatch and screening cells are 2+ at IS, 1+ at 37°C, and negative at the IAT phase. Identify the most likely problem.

A. Combination of antibodies
B. Cold alloantibody
C. Rouleaux
D. Test error

Answer 19

b

Question 20

21. What corrective action should be taken when rouleaux causes positive test results?

A. Perform a saline replacement technique
B. Perform an autoabsorption
C. Run a panel
D. Perform an elution

Answer 20

a

Question 21

22. All of the following are reasons for performing an adsorption, except:

A. Separation of mixtures of antibodies
B. Removal of interfering substances
C. Confirmation of weak antigens on red cells
D. Identification of antibodies causing a positive DAT

Answer 21

d

Question 22

23. How long must a recipient sample be kept in the blood bank following compatibility testing?

A. 3 days
B. 5 days
C. 7 days
D. 10 days

Answer 22

c

Question 23

24. What is the crossmatching protocol for platelets and/or plasma?
    A. Perform a reverse grouping on donor plasma
    B. No testing is required
    C. Perform a reverse grouping on recipient
    plasma
    D. Platelets must be HLA compatible

Answer 23

b

Question 24

25. What are the compatibility requirements for an autologous unit?
A. ABO and Rh typing
B. Type and screen
C. Major crossmatch
D. All of these options

Answer 24

a

Question 25

26. A patient types as AB positive. Two units of blood have been ordered by the physician. Currently, the inventory shows no AB units, 10 A-positive units, 1 A-negative unit, 5 B-positive units, and
    20 O-positive units. Which should be set up for the major crossmatch?

A. A-positive units
B. O-positive units
C. B-positive units
D. Call another blood supplier for type-specific
blood

Answer 25

a

Question 26

27. Which of the following comprises an abbreviated crossmatch?
    A. ABO, Rh, and antibody screen
    B. ABO, Rh, antibody screen, IS crossmatch
    C. Type and screen
    D. ABO, Rh, IS crossmatch

Answer 26

b

Question 27

28. When may an IS crossmatch be performed?
    A. When a patient is being massively transfused
    B. When there is no history of antibodies and the current antibody screen is negative
    C. When blood is being emergency released
    D. When a patient has not been transfused in the past 3 months

Answer 27

b