detection and Identification of Antibodies

Question 1

What determines if a red blood cell antibody is clinically significant?

Answer 1

Shortened RBC survival

Question 2

What is tested in an antibody screen?

Answer 2

Patient serum is tested against group O reagent screening cells

Question 3

Why are screening cells group O?

Answer 3

To prevent interference with anti-a or anti-b in patient serum

Question 4

Antibodies in which of the following blood group systems are “notorious” for escaping detection on an antibody screen and cause a severe delayed hemolytic transfusion reaction when antigen positive red blood cells are transfused to a patient?

Answer 4

Kidd

Question 5

What screening cells are used primarily for testing donor units for unexpected antibodies?

Answer 5

Pooled

Question 6

Why might some blood banking facilities prefer the use of monospecific IgG over polyspecific antihuman globulin (AHG) in their antibody screens?

Answer 6

Interference from naturally occurring cold antibodies in patient sera is reduced

Question 7

Which of the following is known as the “sensitization phase” in the antibody screen?

Answer 7

37 degrees C incubation

Question 8

What makes up an autologous control?

Answer 8

Patient serum and patient cells

Question 9

A positive autocontrol in antibody detection procedures is usually indicative of:

Answer 9

Positive DAT

Question 10

What might a positive antibody screen and a negative autocontrol indicate?

Answer 10

An alloantibody has been detected

Question 11

When should multiple antibodies be suspected in a positive antibody screen?

Answer 11

Cells react and different phases and strengths

Question 12

In what test might rouleaux cause an interference?

Answer 12

Reverse ABO grouping

Question 13

Why is it important to match the lot number on the panel sheet with the lot number on the panel cells?

Answer 13

Pattern of reactions will change from lot to lot

Question 14

Why should only homozygous cells be used to rule out an antibody?

Answer 14

Weakly reacting antibody may not react with heterozygous cells

Question 15

If you suspect anti-C is present in a patient’s serum, and anti-Fya still has to be ruled out using other reagent cells, what would the phenotype of the rule out cell have to be?

Answer 15

Fy (a+), C-, Fy (b-)

Question 16

How would 4 units of red blood cells be found for a patient with antibodies to C, Fya, and Jkb?

Answer 16

random crossmatching patient’s sera followed by phenotyping compatible units of red blood cells

your blood supplier

Question 17

Tests with which AHG reagents can determine if IgG, complement, or both are coating red blood cells?

Answer 17

monospecific

Question 18

Which of the following is a mechanism of an elution procedure?

Answer 18

Disruption of structural complementarity of antigen and antibody

Question 19

What is the most common use of adsorption?

Answer 19

Removal of autoantibody from patient serum

Question 20

In what circumstances would an alloadsorption be performed?

Answer 20

Multiple antibodies in patient serum

Question 21

How can neutralization aid in the identification of multiple antibodies?

Answer 21

Once antibody has been neutralized serum can be further tested in panel studies

Question 22

What test is used to confirm efficacy of chloroquine treatment?

Answer 22

DAT

Question 23

Why are antibodies to high-frequency antigens, such as cellano (k), rarely seen in patient samples?

Answer 23

Most persons are not antigenically stimulated to produce the antibody because their red blood cells are positive for the antigen

Question 24

What would be a realistic source of finding compatible units for a person with an antibody to a high-frequency antigen?

Answer 24

Siblings

Question 25

Which of the following high-frequency antigens do not cause in vivo red blood cell destruction when complexed with corresponding antibody?

Answer 25

Cha

Question 26

Which of the following statements are correct concerning cold antibody screens?

Answer 26

Patient serum is incubated with group O red blood cells at 4 degrees C

Question 27

A person has developed an antibody to the LISS reagent. What test will not be affected by this circumstance?

Answer 27

DAT

Question 28

Why can’t autoadsorption be performed on a patient who was transfused 1 month before?

Answer 28

Donor cells might adsorb out alloantibody in serum

Question 29

What is the purpose of treating serum containing cold autoantibodies with dithiothreitol (DTT) or 2-mercaptoethanol (2-ME)?

Answer 29

To denature IgM cold autoantibody and test serum for presence of IgG alloantibody

Question 30

What test must be performed on a patient with a warm autoantibody in their serum before transfusing?

Answer 30

Warm autoadsorption