Antibody Identification

Question 1

What is the purpose of an antibody screen?

Answer 1

To detect RBC antibodies other than anti-A and anti-B

Question 2

What type of antibodies are detected in an antibody screen?

Answer 2

Unexpected antibodies (0.3-2% of the general population has them)

Question 3

What causes an antibody to be significant?

Answer 3

The ability to shorten RBC survival

Question 4

What test requires testing patient serum against screening cells that contain known antigens?

Answer 4

Antibody screen

Question 5

Screening cells are of which ABO group?

Answer 5

Type O

Question 6

Why are group O cells used in screening cells?

Answer 6

So a patient’s anti-A and/or anti-B will not interfere with the detection of significant unexpected antibodies

Question 7

Term for the list of the antigen makeup of each cell provided with each lot of screening cells issued from a manufacture

Answer 7

anti-gram

Question 8

Ideal screening cells have what type of expression of as many antigens as possible?

Answer 8

homozygous expression

Question 9

Homozygous antigen expression on screening cells is especially helpful when antibodies, such as anti-Jk and anti-M, show what?

Answer 9

dosage

Question 10

What may be a reason a significant antibody goes undetected even though the procedures were followed correctly?

Answer 10

dosage. Some antibodies will only show visible reactions when a cell is homozygous for its corresponding antigen

Question 11

A single vial form of screening cells contains…

Answer 11

No more than 2 donor cells pooled together

Question 12

A two vial form of screening cells contains

Answer 12

2 donors, each in a separate vial

Question 13

A three vial form of screening cells contains…

Answer 13

3 different donors, each in a separate vial

Question 14

The degree of a positive reaction typically indicates…

Answer 14

the amount of antibody present, not its significance

Question 15

What is it called when a patient’s serum is tested against the patient’s RBCs?

Answer 15

autologous control

Question 16

If an autologous control is positive, what other test would you expect to also be positive?

Answer 16

DAT

Question 17

When should agglutination tests be read and why?

Answer 17

directly after centrifugation. Any delay in time can cause the antibodies to elute from the antigens and result in a false-negative.

Question 18

Which immunoglobulin class reacts best at cold temperatures and is capable of causing agglutination with cells suspended in saline?

Answer 18

IgM

Question 19

Which immunoglobulin class reacted best at AHG phase of testing?

Answer 19

IgG

Question 20

A positive antibody screen and a negative autologous control indicates the detections of an

Answer 20

alloantibody

Question 21

A positive antibody screen and a positive autologous control indicates the detection of an

Answer 21

autoantibody

Question 22

What can cause a positive autologous control due to an alloantibody?

Answer 22

recent transfusion

Question 23

Name 2 situations where non-specific agglutination can occur

Answer 23

Multiple myeloma patients and patients on plasma expanders

Question 24

Rouleaux will only interfere with which phase of testing and why?

Answer 24

Rouleaux only interferes with the IS phase, not the AHG phase because the patient’s serum is washed away before the AHG phase

Question 25

What can be used to disperse rouleaux?

Answer 25

1-3 drops of saline