Immuhematology- Testing for Antibodies Flashcards
1
Q
- 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
A
C. Anti-Lea is not a likely antibody because even Leb
individuals secrete some Lea
2
Q
- 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
A
B. Neutralize the serum with saliva
3
Q
- 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
A
A. Blood that is negative for the Leb antigen
4
Q
- 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
A
B. Dosage effect may be seen for both M and N
antigens
5
Q
- 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
A
A. Anti-M may not allow detection of a clinically
significant antibody
6
Q
- 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
A
A. The antibody attaches to RBCs at 4°C and causes
hemolysis at 37°C
7
Q
- 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
A
D. Neutralization with hydatid cyst fluid
8
Q
- Which antibody is frequently seen in patients with
warm autoimmune hemolytic anemia?
A. Anti-Jka
B. Anti-e
C. Anti-K
D. Anti-Fyb
A
B. Anti-e
9
Q
- 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
A
A. Anti-I
10
Q
- 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
A
C. Anti-M, anti-N
11
Q
- Which of the following antibodies
characteristically gives a refractile mixed-field
appearance?
A. Anti-K
B. Anti-Dia
C. Anti-Sda
D. Anti-s
A
C. Anti-Sda
12
Q
- 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
A
C. 95% confidence that the correct antibody has
been identified
13
Q
- 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
A
B. Rarely, because most individuals have the
antigen and therefore would not develop the
antibody
14
Q
- 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
A
B. Run an enzyme panel
15
Q
- 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
A
A. Detected at the IAT phase; may cause hemolytic
disease of the newborn and hemolytic transfusion
reactions
16
Q
- 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
A
A. Crossmatch using units negative for Jka antigen
17
Q
- 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
A
C. High titer low avidity (HTLA)
18
Q
- 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
A
C. Anti-Lub
19
Q
- 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
A
B. Serum stored at 4°C for no longer than 48 hours
20
Q
- Which antibody would not be detected by group
O screening cells?
A. Anti-N
B. Anti-A1
C. Anti-Dia
D. Anti-k
A
B. Anti-A1
21
Q
- 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
A
B. Anti-Jkb
22
Q
- 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
A
D. Anti-C and anti-K
23
Q
- 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
A
B. Anti-C
24
Q
- 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
A
B. 1, 2, 9
25
Q
- 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
A
C. E and c
26
Q
- 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
A
C. One antibody is only reacting with homozygous
cells
