MLS BOC Exam Prep Exam questions
2026 Exam Questions and verified
Answers
The growth results shown in this table are observed on media inoculated with a foot abscess aspirate
and incubated in 3 - 5% CO2.
SBA: 2+ large gray colonies
PEA: no growth
chocolate: 3+ large gray colonies
MAC: 3+ lactose fermenters
thioglycolate: gram-negative bacilli and gram-positive bacilli
Biochemicals are set up on the colonies from the MacConkey agar plate. What should themicrobiologist
do next? - CORRECT ANSWERS subculture TSB to SBA aerobic and SBA anaerobic
What is the appropriate deferral period from donating blood for a 34 year old female who miscarried in
her first trimester? - CORRECT ANSWERS No deferral
Which of the following is responsible for causing transfusion associated graft-versus-host disease? -
CORRECT ANSWERS lymphocytes
The immunoglobulin class responsible for the etiology of HDFN is: - CORRECT ANSWERS IgG
A primary immune response typically presents with which class of antibody? - CORRECT ANSWERS
IgM
,When performing an antibody panel, which one of the following antigens will be destroyed by enzyme
treatment? - CORRECT ANSWERS Fya
Why is Rh immune globulin administered within 72 hours of delivery to an Rh negative mother if
newborn is found to be D-positive or weak-D positive? - CORRECT ANSWERS prevent fetal
cells from initially sensitizing the mother
Which of the following is a possible type for an offspring from the mating of an O and an AB (non-cis)
individual? - CORRECT ANSWERS AO
A newborn presents with neonatal alloimmune thrombocytopenia. What is the most likely cause of this
condition? - CORRECT ANSWERS Maternal antibodies to neonatal platelet antigens
In order to prevent a loss of viability in platelet concentrates during storage, the pH must be maintained
at or above what level? - CORRECT ANSWERS 6.2
Severe blood loss causing circulatory collapse and shock usually first occurs when what percentage of
blood is lost? - CORRECT ANSWERS 30-40%
Which of the following characteristics is consistent with the Kidd blood group system? - CORRECT
ANSWERS Jk(a-b-) red cells are resistant to lysis in 2M urea
If an Rh group (DCe/dce) man marries an Rh group (dce/dce) woman, what is the probability that their
offspring will be D negative? - CORRECT ANSWERS 50%
While ABO, Rh, Kell, Duffy, Kidd, SsU are clinically significant, which of the following antibodies generally
react at only the Coombs phase (AHG)? - CORRECT ANSWERS Kell, Duffy, and Kidd
antibodies
,Which if the first marker (antigen or antibody) which will become positive after exposure to Hep B? -
CORRECT ANSWERS HBsAg
To prevent Rh alloimmunization in pregnancy between mother and fetus, it is recommended to initiate
RhIG prophylaxis when? - CORRECT ANSWERS Rh-negative pregnant females, antenatal in
the third trimester
Which of the following refers to the most common procedure for donating whole blood for use by the
general population? - CORRECT ANSWERS allogeneic donation
Almost all individuals possess which Lutheran antigen profile? - CORRECT ANSWERS Lu(a-b+)
what is the most common possible phenotype of the mating between a mother who has an AB genotype
and a father who has an AO genotype? - CORRECT ANSWERS A
An Rh negative mother has just given birth to an Rh positive baby. Her physician suspects that she has
experienced a fetal-maternal hemmorhage since her rosette test was positive. Upon performing the
Kleihauer-Betke stain procedure, the percentage of fetal cells is found to be 0.85%. The mother's total
blood volume is 4565mL. What dose of Rh immune Globulin should be administered to the mother? -
CORRECT ANSWERS 2 vials
An error was made in a handwritten blood bank record. Which of the following methods is acceptable
for correcting the error to remain in compliance with current good manufacturing practices
requirements? - CORRECT ANSWERS draw a single line through the error so that it can still
be read and add your initials next to it
If an autologous blood component is shipped from the donor center without the completion of
infectious disease testing, the unit must be labeled with: - CORRECT ANSWERS The phrase
"Donor Untested"
, What is the MOST common cause of acute hemolytic transfusion reactions? - CORRECT ANSWERS
clerical errors
What is the cause of MOST severe acute hemolytic transfusions reactions? - CORRECT ANSWERS
ABO incompatibility
Which of the following is the deferral period following the collection of double red blood cell units? -
CORRECT ANSWERS 16 weeks
Which of the following blood groups reacts least strongly with anti-H? - CORRECT ANSWERS
A1B
What is the deferral period from donating blood for someone who is or has taken Tegison for severe
psoriasis? - CORRECT ANSWERS permanent deferral
An antibody screen utilizing polyethylene glycol (PEG) was performed. Reaction readings of this antibody
screen are analyzed after the immediate spin and again at 37*C incubation with subsequent
centrifugation. How will the centrifugation of the tubes affect the patient's results? - CORRECT
ANSWERS false positives may be seen
Which one of the ABO groups listed below has the MOST H antigen? - CORRECT ANSWERS O
Which of the following cells are capable of producing antibodies? - CORRECT ANSWERS
lymphocytes
Which of the following changes in titers would be considered significant when monitoring maternal
antibodies using a doubling dilution? - CORRECT ANSWERS 8 to 32
2026 Exam Questions and verified
Answers
The growth results shown in this table are observed on media inoculated with a foot abscess aspirate
and incubated in 3 - 5% CO2.
SBA: 2+ large gray colonies
PEA: no growth
chocolate: 3+ large gray colonies
MAC: 3+ lactose fermenters
thioglycolate: gram-negative bacilli and gram-positive bacilli
Biochemicals are set up on the colonies from the MacConkey agar plate. What should themicrobiologist
do next? - CORRECT ANSWERS subculture TSB to SBA aerobic and SBA anaerobic
What is the appropriate deferral period from donating blood for a 34 year old female who miscarried in
her first trimester? - CORRECT ANSWERS No deferral
Which of the following is responsible for causing transfusion associated graft-versus-host disease? -
CORRECT ANSWERS lymphocytes
The immunoglobulin class responsible for the etiology of HDFN is: - CORRECT ANSWERS IgG
A primary immune response typically presents with which class of antibody? - CORRECT ANSWERS
IgM
,When performing an antibody panel, which one of the following antigens will be destroyed by enzyme
treatment? - CORRECT ANSWERS Fya
Why is Rh immune globulin administered within 72 hours of delivery to an Rh negative mother if
newborn is found to be D-positive or weak-D positive? - CORRECT ANSWERS prevent fetal
cells from initially sensitizing the mother
Which of the following is a possible type for an offspring from the mating of an O and an AB (non-cis)
individual? - CORRECT ANSWERS AO
A newborn presents with neonatal alloimmune thrombocytopenia. What is the most likely cause of this
condition? - CORRECT ANSWERS Maternal antibodies to neonatal platelet antigens
In order to prevent a loss of viability in platelet concentrates during storage, the pH must be maintained
at or above what level? - CORRECT ANSWERS 6.2
Severe blood loss causing circulatory collapse and shock usually first occurs when what percentage of
blood is lost? - CORRECT ANSWERS 30-40%
Which of the following characteristics is consistent with the Kidd blood group system? - CORRECT
ANSWERS Jk(a-b-) red cells are resistant to lysis in 2M urea
If an Rh group (DCe/dce) man marries an Rh group (dce/dce) woman, what is the probability that their
offspring will be D negative? - CORRECT ANSWERS 50%
While ABO, Rh, Kell, Duffy, Kidd, SsU are clinically significant, which of the following antibodies generally
react at only the Coombs phase (AHG)? - CORRECT ANSWERS Kell, Duffy, and Kidd
antibodies
,Which if the first marker (antigen or antibody) which will become positive after exposure to Hep B? -
CORRECT ANSWERS HBsAg
To prevent Rh alloimmunization in pregnancy between mother and fetus, it is recommended to initiate
RhIG prophylaxis when? - CORRECT ANSWERS Rh-negative pregnant females, antenatal in
the third trimester
Which of the following refers to the most common procedure for donating whole blood for use by the
general population? - CORRECT ANSWERS allogeneic donation
Almost all individuals possess which Lutheran antigen profile? - CORRECT ANSWERS Lu(a-b+)
what is the most common possible phenotype of the mating between a mother who has an AB genotype
and a father who has an AO genotype? - CORRECT ANSWERS A
An Rh negative mother has just given birth to an Rh positive baby. Her physician suspects that she has
experienced a fetal-maternal hemmorhage since her rosette test was positive. Upon performing the
Kleihauer-Betke stain procedure, the percentage of fetal cells is found to be 0.85%. The mother's total
blood volume is 4565mL. What dose of Rh immune Globulin should be administered to the mother? -
CORRECT ANSWERS 2 vials
An error was made in a handwritten blood bank record. Which of the following methods is acceptable
for correcting the error to remain in compliance with current good manufacturing practices
requirements? - CORRECT ANSWERS draw a single line through the error so that it can still
be read and add your initials next to it
If an autologous blood component is shipped from the donor center without the completion of
infectious disease testing, the unit must be labeled with: - CORRECT ANSWERS The phrase
"Donor Untested"
, What is the MOST common cause of acute hemolytic transfusion reactions? - CORRECT ANSWERS
clerical errors
What is the cause of MOST severe acute hemolytic transfusions reactions? - CORRECT ANSWERS
ABO incompatibility
Which of the following is the deferral period following the collection of double red blood cell units? -
CORRECT ANSWERS 16 weeks
Which of the following blood groups reacts least strongly with anti-H? - CORRECT ANSWERS
A1B
What is the deferral period from donating blood for someone who is or has taken Tegison for severe
psoriasis? - CORRECT ANSWERS permanent deferral
An antibody screen utilizing polyethylene glycol (PEG) was performed. Reaction readings of this antibody
screen are analyzed after the immediate spin and again at 37*C incubation with subsequent
centrifugation. How will the centrifugation of the tubes affect the patient's results? - CORRECT
ANSWERS false positives may be seen
Which one of the ABO groups listed below has the MOST H antigen? - CORRECT ANSWERS O
Which of the following cells are capable of producing antibodies? - CORRECT ANSWERS
lymphocytes
Which of the following changes in titers would be considered significant when monitoring maternal
antibodies using a doubling dilution? - CORRECT ANSWERS 8 to 32
