4.5 Compatibility Testing Flashcards
SITUATION: An emergency trauma patient requires transfusion. Six units of blood are ordered stat (immediately). There is no time to draw a patient sample. O-negative blood is issued. When will compatibility testing be performed?
Compatibility testing will be performed when a patient sample is available
How would autoantibodies affect compatibility testing?
ABO, Rh, antibody screen, and crossmatching may show abnormal results
An antibody screen is reactive at the IAT phase of testing with all three cells of a three- cell screen, and the autocontrol is negative. What is a possible explanation for these results?
High-frequency alloantibody or a mixture of alloantibodies
What does a minor crossmatch consist of?
Recipient RBCs and donor plasma
Can crossmatching be performed on October 14 using a patient sample drawn on October 12?
Yes, a new sample would not be needed
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?
Check inventory of A-, B-, and O-negative units
What ABO types may donate to any other ABO type?
O negative
What type(s) of RBC(s) is (are) acceptable to transfuse to an O-negative patient?
O negative
An MLS 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?
Discard the unit
A donor was found to contain anti-K using pilot tubes from the collection procedure. How would this affect the compatibility test?
Compatibility testing would not be affected
Which of the following is not a requirement for electronic crossmatching?
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
There are concordant results of at least one determination of the recipient’s ABO type on file
A patient showed positive results with screening cells and 4 donor units. The patient autocontrol was negative. What is the most likely antibody?
Anti-k
Screening cells and major crossmatch are positive on IS only, and the autocontrol is negative. Identify the problem.
Cold alloantibody
Six units are crossmatched. Five units are compatible, one unit is incompatible, and the recipient’s antibody screen is negative. Identify the problem:
Donor unit may have a positive DAT
An incompatible donor unit is found to have a positive result on DAT. What should be done with the donor unit?
Discard the unit
Screening cells, major crossmatch, and patient autocontrol are positive in all phases. Identify the problem.
Abnormal protein or nonspecific autoantibody
A panel study has revealed the presence of patient alloantibodies. What is the first step in a major crossmatch?
Antigen type patient cells and any donor cells to be crossmatched
What is the disposition of a donor RBC unit that contains an antibody?
The unit may be labeled to indicate that it contains antibody and released into inventory
Given a situation where screening cells, major crossmatch, autocontrol, and DAT (anti- IgG) are all positive, what procedure should be performed next?
Elution followed by a cell panel on the eluate
A major crossmatch and screening cells are 2+ at the IS phase, 1+ at 37°C, and negative at the IAT phase. Identify the most likely problem.
Cold alloantibody
What corrective action should be taken when rouleaux causes positive test results?
Perform a saline replacement technique
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 RBCs
D. Identification of antibodies causing a positive DAT
Identification of antibodies causing a positive DAT
How long must a recipient sample be kept in the blood bank after compatibility testing?
7 days
What is the crossmatching protocol for platelets and/or plasma?
No testing is required
What are the compatibility requirements for an autologous unit?
ABO and Rh typing
A patient is typed 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
A-positive units
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
ABO, Rh, antibody screen, IS crossmatch
When may IS crossmatching be performed?
When there is no history of antibodies and the current antibody screen is negative
