Quiz IH 2023

The immediate-spin (IS) crossmatch is used to detect ABO incompatibility between donor red cells (RBCs) and the serum of the intended recipient

• Yes

• No

• Not sure

What are mixed fields in the forward grouping usually caused by?

• Group O transfusion

• A3 or B3 phenotype

• Stem cell transplant

• All of the above

What is usually the cause of missing or weak antibodies in the reverse grouping?

• Elderly patient

• Newborn

• immunocompromised

• All of the above

In determining the phenotype for the ABO blood system:

• O is dominant over A

• A is dominant over B

• O is recessive

• None of the above

Crossmatch of the eluate with A group RBC was incompatible, implying that the incompatibility was due to anti-A antibody

• True

• False

• Not sure

A patient has a positive antibody screen and positive results against cells in the antibody panel. The patient specimen is retested with antibody panel cells that have been treated with the enzyme "papain." The antibody no longer reacts against cells in the antibody panel. Which of the following antibodies is most consistent with these results?

• anti-D

• anti-M

• anti-K

• anti-Lea

Answer explanation

enhanced by enzyme

Rh, Kidd, Lewis, P1pk, I

destroyed by enzyme

MNS destroyed, Duffy, Xga

Unaffected

K

At the indirect antiglobulin phase of testing, there is no agglutination between patient serum and screening cells. One of 3 donor units was incompatible.The most probable explanation for these findings is/are that the:

• 1. A) Donor cells with positive DAT

• 1. B) patient has an antibody directed against a low incidence antigen

• 1. C) donor has a positive antibody screen

• D) A and B

When a patient makes an immune antibody, red cell products are phenotyped and antigen negative red cells for corresponding antibody will be provided. Which antibody will be pre-phenotype in advance?

• anti-K

• Anti-E

• anti-D

• anti-A

Answer explanation

All blood products are pre-phenotyped for the D antigen. This is the first and most important antigen in the 55 antigen Rh system.

D antigen is so immunogenic that we do not wait for the patient to make the antibody. A D-negative patient that is exposed to a full unit of RBCs has about a 22% chance of making Anti-D.