Detection & ID of antibodies

Question 1

1. Based on the following phenotypes, which pair of cells
   would make the best screening cells?

a. Cell 1: Group A, D+C+c–E–e+, K+, Fy(a+b–), Jk(a+b–), M+N–S+s–

Cell 2: Group O, D+C–c+E+e–, K–, Fy(a–b+), Jk(a–b+), M–N+S–s+

b. Cell 1: Group O, D–C–c+E–e+, K–, Fy(a–b+), Jk(a+b+), M+N–S+s+

Cell 2: Group O, D+C+c–E–e+, K–, Fy(a+b–), Jk(a+b–), M–N+S–s+

c. Cell 1: Group O, D+C+c+E+e+, K+, Fy(a+b+), Jk(a+b+), M+N–S+s+

Cell 2: Group O, D–C–c+E–e+, K–, Fy(a+b–), Jk(a+b+), M+N+S–s+

d. Cell 1: Group O, D+C+c–E–e+, K+, Fy(a–b+), Jk(a–b+), M–N+S–s+

Cell 2: Group O, D- C–c+E+e–, K–, Fy(a+b–), Jk(a+b–), M+N–S+s–

Answer 1

d. Cell 1: Group O, D+C+c–E–e+, K+, Fy(a–b+), Jk(a–b+), M–N+S–s+

Cell 2: Group O, D- C–c+E+e–, K–, Fy(a+b–), Jk(a+b–), M+N–S+s–

Question 2

2. Antibodies are excluded using RBCs that are homozygous
   for the corresponding antigen because:
   a. Antibodies may show dosage
   b. Multiple antibodies may be present
   c. It results in a P value of 0.05 for proper identification
   of the antibody
   d. All of the above

Answer 2

a. Antibodies may show dosage

Question 3

3. A request for 8 units of RBCs was received for patient LF.
   The patient has a negative antibody screen, but 1 of the
   8 units was 3+ incompatible at the AHG phase. Which of
   the following antibodies may be the cause?
   a. Anti-K
   b. Anti-Lea
   c. Anti-Kpa
   d. Anti-Fyb

Answer 3

c. Anti-Kpa

Question 4

4.. The physician has requested 2 units of RBCs for patient
DB, who has two antibodies, anti-L and anti-Q. The frequency of antigen L is 45%, and the frequency of antigen
Q is 70% in the donor population. Approximately how
many units will need to be antigen-typed for L and Q to
fill the request?
a. 8
b. 12
c. 2
d. 7

Answer 4

b. 12

Question 5

5. Anti-Sda has been identified in patient ALF. What substance would neutralize this antibody and allow detection
   of other alloantibodies?
   a. Saliva
   b. Hydatid cyst fluid
   c. Urine
   d. Human breast milk

Answer 5

c. Urine

Question 6

6. Patient JM appears to have a warm autoantibody. She was
   transfused 2 weeks ago. What would be the next step performed to identify any alloantibodies that might be in her
   serum?
   a. Acid elution
   b. Warm autoadsorption using autologous cells
   c. Warm differential adsorption
   d. RESt adsorption

Answer 6

c. Warm differential adsorption

Question 7

7. What is the titer and score for this prenatal anti-D titer?
   (Refer to Fig. 10–17.)
   a. Titer = 64; score = 52
   b. Titer = 1:32; score = 15
   c. Titer = 64; score = 21
   d. Titer = 32; score = 52

Answer 7

d. Titer = 32; score = 52

Question 8

8. Select the antibody(ies) most likely responsible for the
   reactions observed.
   a. Anti-E and anti-K
   b. Anti-Fya
   c. Anti-e
   d. Anti-Jkb

Question 9

9. What additional cells need to be tested to be 95% confident that the identification is correct?
   a. Three e-negative cells that react negatively and one
   additional e-positive cell that reacts positively
   b. One additional E-positive, K-negative cell to react
   positively and one additional K-positive, E-negative
   cell to react positively
   c. Two Jkb homozygous positive cells to react positively and one Jkb heterozygous positive cell to react
   negatively
   d. No additional cells are needed

Question 10

10. Using the panel (Fig. 10–18), select cells that would make
    appropriate controls when typing for the C antigen.
    a. Cell number 1 for the positive control and cell number 2 for the negative control
    b. Cell number 1 for the positive control and cell number 6 for the negative control
    c. Cell number 2 for the positive control and cell number 4 for the negative control
    d. Cell number 4 for the positive control and cell number 5 for the negative control

Question 11

11. Which of the following methods may be employed to remove IgG antibodies that are coating a patient’s red
    blood cells?
    a. Adsorption
    b. Elution
    c. Neutralization
    d. Titration

Question 12

12. A technologist has decided to test an enzyme-treated
    panel of RBCs against a patient’s serum. Which of the
    following antibody pairs could be separated using this
    technique?
    a. Anti-Jka and anti-Jkb
    b. Anti-S and anti-Fya
    c. Anti-D and anti-C
    d. Anti-Jka and anti-Fya

Question 13

13. An antibody demonstrates weak reactivity at the AHG
    phase when the tube method is used with no enhancement reagent and monospecific anti-IgG AHG reagent.
    When repeating the test, which of the following actions
    may increase the strength of the positive reactions?
    a. Adding an enhancement reagent, such as LISS or PEG
    b. Decreasing the incubation time from 30 minutes to
    10 minutes
    c. Employing the prewarm technique
    d. Decreasing the incubation temperature to 18°C