Deck 8: Compatibility Testing

Question 1

A recipient phenotypes as group O with the following Rh phenotype: D+C+c-E+e+. If this recipient is transfused with red blood cells from six random group O D-positive donors, what Rh alloantibody could this patient produce as a result of transfusion?

A) Anti-E
B) Anti-C
C) Anti-c
D) Anti-D

Answer 1

C
Although Rh phenotyping is not routinely performed, exposure to the c antigen may cause the recipient to make anti-c because the recipient is negative for the antigen.

Question 2

Which of the following tests is not included in routine compatibility testing?

A) ABO phenotyping
B) Direct antiglobulin test
C) D typing
D) Antibody screen

Answer 2

B
The direct antiglobulin test is not required as part of the compatibility test.

Question 3

What are the two components of the major crossmatch?

A) Recipient red cells and donor serum
B) Donor red cells and recipient serum
C) Reverse ABO cells and recipient serum
D) Screening cells and donor serum

Answer 3

B
Donor serum and patient red cells are tested for reactivity.

Question 4

Which of the following blood products requires a crossmatch to be performed before issuing?

A) Group AB fresh frozen plasma that is transfused to a group O
B) Human leukocyte antigen-matched platelets
C) Cryoprecipitated AHF
D) Granulocyte concentrates that have more than 2 mL of red blood cells

Question 5

If the recipient was transfused within the last 3 months, how long from the time of collection can a sample be used for the crossmatch?

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

Question 6

How long following transfusion must the recipient sample be stored?

A) 5 days
B) 7 days
C) 10 days
D) 14 days

Question 7

Antibody screening of the recipient is performed as a component of compatibility testing to detect:

A) red cell alloantibodies.
B) irregular antigens on the recipient's red cells.
C) human leukocyte antigen antibodies.
D) incompatibilities with the donor's red cells.

Question 8

An antibody screen on a patient with a prior history of transfusion was negative. The crossmatch, performed at immediate spin and antihuman globulin, was incompatible with 1 unit selected. The next step in the investigation would be to:

A) perform a panel on the patient's serum.
B) perform a direct antiglobulin test on the incompatible unit.
C) redraw the patient and begin a new crossmatch.
D) crossmatch a new unit and discard the incompatible unit.

Question 9

An infant less than 4 months old requires which procedures for compatibility testing?

A) Antibody screen with each unit released in a 48-hour period
B) ABO and D typing and antibody screen initially only; units released without additional testing if the screen is negative
C) Immediate spin crossmatch with each unit released
D) Group O, D-negative units; no testing is necessary

Question 10

Patient M.M. was admitted to the hospital with acute bleeding. Anti-E was detected in the patient's serum. Four E-negative units of blood were crossmatched for the patient. The units were compatible at immediate spin and following the antiglobulin test. After the antiglobulin test was performed, IgG sensitized red cells gave a 2+ agglutination reaction. The proper interpretation of this 2+ agglutination reaction is the:

A) antihuman globulin washing procedure was adequate.
B) IgG-sensitized red cells spontaneously agglutinated.
C) crossmatch was incompatible.
D) patient's anti-E reacted with the IgG-sensitized red cells.

Question 11

Antibodies detected in the immediate spin crossmatch are usually of which of the following immunoglobulin classes?

A) IgA
B) IgM
C) IgG
D) IgD

Question 12

When group O blood is not available for transfusion, what is the next alternative?

A) Group A red blood cells
B) Group AB red blood cells
C) Washed group B red blood cells
D) None

Question 13

The immediate spin or abbreviated crossmatch is an acceptable procedure if the recipient:

A) has no prior or existing clinically significant antibodies.
B) has never been pregnant or transfused.
C) needs blood before a sample can be obtained.
D) is using blood from a directed donation.

Question 14

Select the correct statement regarding the collection of a blood sample for compatibility testing.

A) The sample must be labeled at the bedside.
B) The sample requires a new numeric identifier for the patient for each admittance.
C) The sample may be labeled at any time in an emergency.
D) The sample does not require a means to identify the phlebotomist.

Question 15

Compatibility procedures will address all of the following except to:

A) prevent antibody formation.
B) prevent life-threatening transfusion reactions.
C) maximize in vivo survival rate of red cells.
D) check ABO compatibility.

Question 16

For autologous units transfused within the collection facility, which part of the compatibility procedure is not required?

A) ABO phenotyping
B) D phenotyping
C) Antibody screen
D) Transfusion history check

Question 17

If an emergency exists and there is not enough time to perform a crossmatch for red cells, what is the correct procedure?

A) Release group O, D-negative whole blood.
B) Release group O, D-negative red blood cells.
C) Release group AB fresh frozen plasma until the blood type is performed.
D) Release ABO compatible blood based on the patient's prior record in the computer.

Question 18

Your blood bank mistakenly transfused 1 unit of D-positive red blood cells to a patient who was typed as D-negative. The patient had no history of a previous transfusion or pregnancy. Antibody detection testing was negative in pretransfusion testing. The crossmatch in this case was:

A) compatible at immediate spin.
B) incompatible at immediate spin only.
C) not necessary to perform.
D) incompatible at antihuman globulin only.

Question 19

A group O patient was crossmatched with group B red blood cells. What phase of the crossmatch will first detect this incompatibility?

A) Immediate spin
B) 37 ^$\circ$ C low-ionic strength solution
C) Indirect antiglobulin
D) None of them; unit is compatible

Question 20

Given the following red cell antigen frequencies:
Which of the following red cell alloantibodies would be responsible for incompatible crossmatches with one 1 of 10 random donor units?

A) Anti-K
B) Anti-E
C) Anti-k
D) Anti-P₁

Question 21

The use of the electronic (computer) crossmatch is restricted to recipients who:

A) are group O.
B) do not have a clinically significant antibody.
C) have had successful transfusions in the past.
D) have transfusion history that has been documented in the computer.

Question 22

All of the following may be used to perform an antibody screen for an infant less than 4 months old except:

A) infant serum.
B) paternal serum.
C) maternal serum.
D) infant eluate.

Question 23

To what does the abbreviation "MSBOS" refer?

A) Monthly surgical blood order schedule
B) Minimum surgical blood order staffing
C) Maximum blood order schedule
D) Minimum safe blood order schedule

Question 24

In which phase of reactivity would rouleaux typically be detected in the screen?

A) 4 ^$\circ$ C
B) 15 ^$\circ$ C
C) 37 ^$\circ$ C
D) Antihuman globulin

Question 25

In which of the following situations can the crossmatch test be omitted?

A) In a patient who is receiving a directed donation
B) In a patient who has received a massive transfusion within a 24-hour period
C) In a patient who is pregnant
D) In a bone marrow transplant recipient

Question 26

To increase the sensitivity of the antibody screen in a compatibility test, what can be done?

A) Extend the incubation time.
B) Increase the serum to cell ratio.
C) Use an enhancement such as polyethylene glycol.
D) All of the above.