Pretransfusion Testing

Question 1

Mixing patient serum and donor red cells together and observing for direct cell lysis or agglutination is known as:

Answer 1

Major crossmatch

Question 2

What does compatibility testing include?

Answer 2

ABO, Rh, antibody screen, major crossmatch

Question 3

Why are hemolyzed samples unacceptable for compatibility testing?

Answer 3

Complement activation by antigen-antibody complexes will be masked

Question 4

How long after a transfusion must donor and recipient samples be stored at 1 to 6 degrees C?

Answer 4

7 days

Question 5

All of the following antibodies are clinically significant except:

Answer 5

Anti-Bga

Question 6

Why is it necessary to use single-donor screening cells instead of pooled screening cells for patient samples?

Answer 6

Single-donor screening cells are complementary among each other

Question 7

What alternative type can be given to an O-positive person when group O blood is not available?

Answer 7

none

Question 8

In what circumstances would it be feasible to transfuse Rh-positive blood to an Rh-negative individual?

Answer 8

In an elderly woman

Question 9

Which statement best describes the relation between a crossmatch and a compatibility test?

Answer 9

If a compatibility test was a pie, a crossmatch would be a slice

Question 10

Why was the minor crossmatch discontinued?

Answer 10

Donor screening for antibody was incorporated into donor processing

Question 11

What is an abbreviated crossmatch?

Answer 11

Type and screen plus immediate spin crossmatch

Question 12

What is an “electronic” crossmatch?

Answer 12

Comparison of donor and patient ABO groups and serologic data from a computer file

Question 13

All of the following may be used as potentiators in the antiglobulin crossmatch except:

Answer 13

Papain

Question 14

When performing an Antiglobulin crossmatch, the cells had a jagged edge appearance after the addition of AHG and centrifugation. This indicates a(n) ______ result.

Answer 14

Positive

Question 15

Recipients serum which reacted with one out of five donor units in the AHG phase and where the antibody screen was negative is probably due to:

Answer 15

An alloantibody directed towards a low-frequency antigen

Question 16

Passive acquisition of anti-A, B, AB may occur through:

Answer 16

Bone marrow transplantation

Question 17

What causes rouleaux to form?

Answer 17

Abnormal A/G ratio

Question 18

Which of the following is true regarding blood issued on an emergency basis without patient testing?

Answer 18

Units are tagged for emergency release and segments are pulled later for testing

Question 19

How can the ABO and Rh of the fetus be determined in utero?

Answer 19

Amniocentesis
Chorionic Villus sampling
Percutaneous umbilical cord sampling

Question 20

All of the following may be used for the antibody screen before transfusing an infant except:

Answer 20

Paternal serum

Question 21

What may be added to samples from patients taking heparin to induce clotting?

Answer 21

Protamine sulfate

Question 22

What tests are not required on autologous units transfused within the collecting facility?

Answer 22

Antibody screen

Question 23

Why is the transfusion product tagged before it is issued and transfused?

Answer 23

to identify the patient
to verify compatibility results
to verify the donor number

Question 24

What blood-banking research product hopes to provide oxygen-carrying capacity without the need for compatibility testing?

Answer 24

Hemoglobin substitutes