Immunohematology Questions with
100% Correct Answers
*Meiosis in cell division is limited to the ova and
sperm producing four gametes containing what
complement of DNA?
A. 1N
B. 2N
C. 3N
D. 4N Correct Answer: A. Meiosis involves two nuclear divisions in succession
resulting in four gametocytes each containing half the number of chromosomes
found in somatic cells or 1N.
*The alleged father of a child in a disputed case of paternity is blood group AB.
The mother is group O and the child is group O. What type of exclusion is this?
A. Direct/primary/first order
B. Probability
C. Random
D. Indirect/secondary/second order Correct Answer: D. An
indirect/secondary/second order exclusion occurs when a genetic marker is
absent in the child but should have been transmitted by the alleged father. In
this case, either A or B should be present in the child.
,*Blood is crossmatched on an A positive person with
a negative antibody screen. The patient received a
transfusion of A positive RBCs 3 years ago. The
donors chosen for crossmatch were A positive.
The crossmatch was run on the Ortho Provue and
yielded 3+ incompatibility. How can these results
be explained?
A. The patient has an antibody to a low-frequency
antigen
B. The patient has an antibody to a high-frequency
antigen
C. The patient is an A2 with anti-A1
D. The patient is an A1 with anti-A2 Correct Answer: C. The patient is likely an A2
with anti-A1 which is
causing reactivity in the crossmatch. A negative
antibody screen rules out the possibility of an
antibody to a high-frequency antigen, and two
donor units incompatible rules out an antibody to
,a low-frequency antigen.
*What type RBCs can be transfused to an A2 person
with anti-A1?
A. A only
B. A or O
C. B
D. AB Correct Answer: B. A person in need of an RBC transfusion who is an A2
with anti-A1 can be transfused A or O cells because the anti-A1 is typically only
reactive at room
temperature.
*What should be done if all forward and reverse
ABO results are negative?
A. Perform additional testing such as typing with
anti-A1 lectin and anti-A,B
B. Incubate at 22°C or 4°C to enhance weak
expression
C. Repeat the test with new reagents
D. Run an antibody identification panel Correct Answer: B. All negative results
may be due to weakened
, antigens or antibodies. Room temperature or lower
incubation temperature may enhance expression of
weakened antigens or antibodies.
*Which condition would most likely be responsible
for the following typing results?
Patient cells: Anti-A, neg Anti-B, neg
Patient serum: A1 cells, neg B cells, 4+
A. Immunodeficiency
B. Masking of antigens by the presence of massive
amounts of antibody
C. Weak or excessive antigen(s)
D. Impossible to determine Correct Answer: C. Excessive A substance, such as
may be found in some types of tumors, may be neutralizing the anti-A. Weak A
subgroups may fail to react with anti-A and require additional testing
techniques (e.g., room-temperature incubation) before their expression is
apparent.
*A 61-year-old male with a history of multiple
myeloma had a stem cell transplant 3 years ago.
The donor was O positive and the recipient was
100% Correct Answers
*Meiosis in cell division is limited to the ova and
sperm producing four gametes containing what
complement of DNA?
A. 1N
B. 2N
C. 3N
D. 4N Correct Answer: A. Meiosis involves two nuclear divisions in succession
resulting in four gametocytes each containing half the number of chromosomes
found in somatic cells or 1N.
*The alleged father of a child in a disputed case of paternity is blood group AB.
The mother is group O and the child is group O. What type of exclusion is this?
A. Direct/primary/first order
B. Probability
C. Random
D. Indirect/secondary/second order Correct Answer: D. An
indirect/secondary/second order exclusion occurs when a genetic marker is
absent in the child but should have been transmitted by the alleged father. In
this case, either A or B should be present in the child.
,*Blood is crossmatched on an A positive person with
a negative antibody screen. The patient received a
transfusion of A positive RBCs 3 years ago. The
donors chosen for crossmatch were A positive.
The crossmatch was run on the Ortho Provue and
yielded 3+ incompatibility. How can these results
be explained?
A. The patient has an antibody to a low-frequency
antigen
B. The patient has an antibody to a high-frequency
antigen
C. The patient is an A2 with anti-A1
D. The patient is an A1 with anti-A2 Correct Answer: C. The patient is likely an A2
with anti-A1 which is
causing reactivity in the crossmatch. A negative
antibody screen rules out the possibility of an
antibody to a high-frequency antigen, and two
donor units incompatible rules out an antibody to
,a low-frequency antigen.
*What type RBCs can be transfused to an A2 person
with anti-A1?
A. A only
B. A or O
C. B
D. AB Correct Answer: B. A person in need of an RBC transfusion who is an A2
with anti-A1 can be transfused A or O cells because the anti-A1 is typically only
reactive at room
temperature.
*What should be done if all forward and reverse
ABO results are negative?
A. Perform additional testing such as typing with
anti-A1 lectin and anti-A,B
B. Incubate at 22°C or 4°C to enhance weak
expression
C. Repeat the test with new reagents
D. Run an antibody identification panel Correct Answer: B. All negative results
may be due to weakened
, antigens or antibodies. Room temperature or lower
incubation temperature may enhance expression of
weakened antigens or antibodies.
*Which condition would most likely be responsible
for the following typing results?
Patient cells: Anti-A, neg Anti-B, neg
Patient serum: A1 cells, neg B cells, 4+
A. Immunodeficiency
B. Masking of antigens by the presence of massive
amounts of antibody
C. Weak or excessive antigen(s)
D. Impossible to determine Correct Answer: C. Excessive A substance, such as
may be found in some types of tumors, may be neutralizing the anti-A. Weak A
subgroups may fail to react with anti-A and require additional testing
techniques (e.g., room-temperature incubation) before their expression is
apparent.
*A 61-year-old male with a history of multiple
myeloma had a stem cell transplant 3 years ago.
The donor was O positive and the recipient was
