Immuhematology- Testing for Antibodies

Question 1

1. A patient has the Lewis phenotype Le(a−b−). An
   antibody panel reveals the presence of anti-Lea.
   Another patient with the phenotype Le(a−b+) has
   a positive antibody screen; however, a panel
   reveals no conclusive antibody. Should anti-Lea be
   considered as a possibility for the patient with the
   Le(a−b+) phenotype?
   A. Anti-Lea should be considered as a possible
   antibody
   B. Anti-Lea may be a possible antibody, but further
   studies are needed
   C. Anti-Lea is not a likely antibody because even Leb
   individuals secrete some Lea
   D. Anti-Lea may be found in saliva but not
   detectable in serum

Answer 1

C. Anti-Lea is not a likely antibody because even Leb
individuals secrete some Lea

Question 2

2. A technologist is having great difficulty resolving
   an antibody mixture. One of the antibodies is antiLea. This antibody is not clinically significant in
   this situation, but it needs to be removed to reveal
   the possible presence of an underlying antibody of
   clinical significance. What can be done?
   A. Perform an enzyme panel
   B. Neutralize the serum with saliva
   C. Neutralize the serum with hydatid cyst fluid
   D. Use DTT (dithiothreitol) to treat the panel cells

Answer 2

B. Neutralize the serum with saliva

Question 3

3. What type of blood should be given to an
   individual who has an anti-Leb that reacts 1+ at
   the IAT phase?
   A. Blood that is negative for the Leb antigen
   B. Blood that is negative for both the Lea and Leb
   antigens
   C. Blood that is positive for the Leb antigen
   D. Lewis antibodies are not clinically significant, so
   any type of blood may be given

Answer 3

A. Blood that is negative for the Leb antigen

Question 4

4. Which of the following statements is true
   concerning the MN genotype?
   A. Antigens are destroyed using bleach-treated cells
   B. Dosage effect may be seen for both M and N
   antigens
   C. Both M and N antigens are impossible to detect
   because of cross-interference
   D. MN is a rare phenotype seldom found in routine
   antigen typing

Answer 4

B. Dosage effect may be seen for both M and N
antigens

Question 5

5. Anti-M is sometimes found with reactivity
   detected at the immediate spin (IS) phase that
   persists in strength to the IAT phase. What is the
   main testing problem with a strong anti-M?
   A. Anti-M may not allow detection of a clinically
   significant antibody
   B. Compatible blood may not be found for the
   patient with a strongly reacting anti-M
   C. The anti-M cannot be removed from the serum
   D. The anti-M may react with the patient’s own
   cells, causing a positive autocontro

Answer 5

A. Anti-M may not allow detection of a clinically
significant antibody

Question 6

6. A patient is suspected of having paroxysmal
   cold hemoglobinuria (PCH). Which pattern
   of reactivity is characteristic of the Donath–
   Landsteiner antibody, which causes this condition?
   A. The antibody attaches to RBCs at 4°C and causes
   hemolysis at 37°C
   B. The antibody attaches to RBCs at 37°C and
   causes agglutination at the IAT phase
   C. The antibody attaches to RBCs at 22°C and
   causes hemolysis at 37°C
   D. The antibody attaches to RBCs and causes
   agglutination at the IAT phase

Answer 6

A. The antibody attaches to RBCs at 4°C and causes
hemolysis at 37°C

Question 7

7. How can interfering anti-P1 antibody be removed
   from a mixture of antibodies?
   A. Neutralization with saliva
   B. Agglutination with human milk
   C. Combination with urine
   D. Neutralization with hydatid cyst fluid

Answer 7

D. Neutralization with hydatid cyst fluid

Question 8

8. Which antibody is frequently seen in patients with
   warm autoimmune hemolytic anemia?
   A. Anti-Jka
   B. Anti-e
   C. Anti-K
   D. Anti-Fyb

Answer 8

B. Anti-e

Question 9

9. An antibody shows strong reactions in all test
   phases. All screen and panel cells are positive. The
   serum is then tested with a cord cell and the
   reaction is negative. What antibody is suspected?
   A. Anti-I
   B. Anti-i
   C. Anti-H
   D. Anti-p

Answer 9

A. Anti-I

Question 10

10. Which group of antibodies is commonly found as
    cold agglutinins?
    A. Anti-K, anti-k, anti-Jsb
    B. Anti-D, anti-e, anti-C
    C. Anti-M, anti-N
    D. Anti-Fya, anti-Fyb

Answer 10

C. Anti-M, anti-N

Question 11

11. Which of the following antibodies
    characteristically gives a refractile mixed-field
    appearance?
    A. Anti-K
    B. Anti-Dia
    C. Anti-Sda
    D. Anti-s

Answer 11

C. Anti-Sda

Question 12

12. What does the 3+3 rule ascertain?
    A. An antibody is ruled in
    B. An antibody is ruled out
    C. 95% confidence that the correct antibody has
    been identified
    D. 95% confidence that the correct antibody has
    not been identified

Answer 12

C. 95% confidence that the correct antibody has
been identified

Question 13

13. The k (Cellano) antigen is a high-frequency
    antigen and is found on most red cells. How
    often would one expect to find the corresponding
    antibody?
    A. Often, because it is a high frequency antibody
    B. Rarely, because most individuals have the
    antigen and therefore would not develop the
    antibody
    C. It depends upon the population, because certain
    racial and ethnic groups show a higher frequency
    of anti-k
    D. Impossible to determine without consulting
    regional blood group antigen charts

Answer 13

B. Rarely, because most individuals have the
antigen and therefore would not develop the
antibody

Question 14

14. Which procedure would help to distinguish
    between an anti-e and anti-Fya in an antibody
    mixture?
    A. Lower the pH of test serum
    B. Run an enzyme panel
    C. Use a thiol reagent
    D. Run a LISS pane

Answer 14

B. Run an enzyme panel

Question 15

15. Which characteristics are true of all three of
    the following antibodies: anti-Fya, anti-Jka,
    and anti-K?
    A. Detected at the IAT phase; may cause hemolytic
    disease of the newborn and hemolytic transfusion
    reactions
    B. Not detected with enzyme-treated cells
    C. Requires the IAT technique for detection;
    usually not associated with HDN
    D. Enhanced reactivity with enzyme-treated cells;
    may cause severe hemolytic transfusion reactions

Answer 15

A. Detected at the IAT phase; may cause hemolytic
disease of the newborn and hemolytic transfusion
reactions

Question 16

16. A patient is admitted to the hospital. Medical
    records indicate that the patient has a history of
    anti-Jka. When you performed the type and screen,
    the type was O positive and screen was negative.
    You should:
    A. Crossmatch using units negative for Jka antigen
    B. Crossmatch random units, since the antibody is
    not demonstrating
    C. Request a new sample
    D. Repeat the screen with enzyme-treated screening
    cells

Answer 16

A. Crossmatch using units negative for Jka antigen

Question 17

17. A technologist performs an antibody study and
    finds 1+ and weak positive reactions for several of
    the panel cells. The reactions do not fit a pattern.
    Several selected panels and a patient phenotype do
    not reveal any additional information. The serum
    is diluted and retested, but the same reactions
    persist. What type of antibody may be causing
    these results?
    A. Antibody to a high-frequency antigen
    B. Antibody to a low-frequency antigen
    C. High titer low avidity (HTLA)
    D. Anti-HLA

Answer 17

C. High titer low avidity (HTLA)

Question 18

18. An antibody is detected in a pregnant woman and
    is suspected of being the cause of fetal distress. The
    antibody reacts at the IAT phase but does not react
    with DTT-treated cells. This antibody causes in
    vitro hemolysis. What is the most likely antibody
    specificity?
    A. Anti-Lea
    B. Anti-Lua
    C. Anti-Lub
    D. Anti-Xga

Answer 18

C. Anti-Lub

Question 19

19. What sample is best for detecting complementdependent antibodies?
    A. Plasma stored at 4°C for no longer than
    24 hours
    B. Serum stored at 4°C for no longer than 48 hours
    C. Either serum or plasma stored at 20°C–24°C no
    longer than 6 hours
    D. Serum heated at 56°C for 30 minutes

Answer 19

B. Serum stored at 4°C for no longer than 48 hours

Question 20

20. Which antibody would not be detected by group
    O screening cells?
    A. Anti-N
    B. Anti-A1
    C. Anti-Dia
    D. Anti-k

Answer 20

B. Anti-A1

Question 21

21. Refer to Panel 1. Which antibody is most likely
    implicated?
    A. Anti-Fyb
    B. Anti-Jkb
    C. Anti-e
    D. Anti-c and anti-K

Answer 21

B. Anti-Jkb

Question 22

22. Refer to Panel 2. Which antibody specificity is
    most likely present?
    A. Anti-S and anti-E
    B. Anti-E and anti-K
    C. Anti-Lea and anti-Fyb
    D. Anti-C and anti-K

Answer 22

D. Anti-C and anti-K

Question 23

23. On Panel 2, which of the following antibodies
    could not be ruled out?
    A. Anti-Jkb
    B. Anti-C
    C. Anti-M
    D. Anti-Fyb

Answer 23

B. Anti-C

Question 24

24. On Panel 2, which cells are homozygous for C?
    A. 1, 2, 3
    B. 1, 2, 9
    C. 3, 4, 7
    D. 7, 8, 10

Answer 24

B. 1, 2, 9

Question 25

25. A 77-year-old female is admitted to a community
    hospital after a cardiac arrest. History includes an
    abdominal aortic aneurysm 2 years ago in which
    she received 6 units of packed cells. Her blood type
    is A positive and antibody screen is positive at
    AHG phase in screening cells II and III. A panel
    is performed using LISS. Referring to panel 3,
    which antibodies are likely implicated?
    A. C and K
    B. Jka and c
    C. E and c
    D. Fya and M

Answer 25

C. E and c

Question 26

26. What observation is apparent with one of the
    antibodies present on Panel 3?
    A. One antibody is only reacting with heterozygous
    cells
    B. Both antibodies are only reacting with
    homozygous cells
    C. One antibody is only reacting with homozygous
    cells
    D. Both antibodies are exhibiting dosage

Answer 26

C. One antibody is only reacting with homozygous
cells