ABO ADVANCED COMPREHENSIVE
STUDY GUIDE 2026 FULL QUESTIONS
AND SOLUTIONS GRADED A+
◍ An amsler's grid should be used on a daily basis for patients
with_____________.
Answer: Macular degeneration
◍ What is an ABO discrepancy?.
Answer: An ABO discrepancy is present when there is a disagreement
between Rh and ABO typing, forward and reverse typing, a positive
antibody screen, or a positive Direct Antiglobulin Test (DAT).
◍ Why must ABO discrepancies be resolved before transfusion?.
Answer: ABO discrepancies must be resolved before transfusion because
forward and reverse typing disagreement can lead to unsafe blood selection.
◍ Which of the following is used to check for lateral and vertical phorias.
Answer: Maddox rod
◍ What is one of the 4 major ABO discrepancy categories?.
Answer: One of the 4 major ABO discrepancy categories is 'Missing or
weak antigen.'
◍ A patient will experience photo phobia and Poor near vision
after____________.
Answer: Cycloplegic refraction
◍ If the patient says that the green side is clearer during the binocular
duochrome test, you should add_______O
U. .
Answer: Plus power
,◍ The physiologic blind spot is located where.
Answer: optic disk
◍ What is another major ABO discrepancy category?.
Answer: Another major ABO discrepancy category is 'Missing or weak
antibody.'
◍ What type of discrepancy would a very weak subgroup of A or B most
likely cause?.
Answer: A very weak subgroup of A or B would most likely cause a
'Missing or weak antigen' discrepancy.
◍ What is associated with loss of transferase in acute leukemia?.
Answer: Loss of transferase in acute leukemia is associated with 'missing or
weak antigen.'
◍ The near point of convergence is reached when the test object:.
Answer: Gets so close it blurs
◍ When measuring a patient with a horizontal deviation, the Maddox rod
should be positioned so that the line forms a__________.
Answer: Vertical line
◍ The instrument that provides information on the patient refractive status by
reflecting light off the retina is_____________.
Answer: Retniscope
◍ What may massive transfusion of group O blood cause?.
Answer: Massive transfusion of group O blood may cause a 'missing or
weak antibody discrepancy.'
◍ How may bone marrow transplant contribute to ABO discrepancies?.
Answer: Bone marrow transplant may contribute to both 'missing or weak
antigen' and 'missing or weak antibody' discrepancies.
◍ What is an appropriate resolution step for a missing or weak antigen
discrepancy?.
Answer: An appropriate resolution step is to incubate the front type at room
, temperature or 4-22°C for at least 15 minutes.
◍ Which reagent may react better with some weak A or B subgroups?.
Answer: Anti-A1 lectin may react better with some weak A or B subgroups.
◍ If a patient misses two letters on the 20/30 acuity line, the acuity should be
recorded as.
Answer: 20/30-2
◍ What is a cause of missing or weak antibody in reverse typing?.
Answer: A cause of missing or weak antibody in reverse typing is advanced
age.
◍ If the patient sees the red side clearer during a monocular duochrome test
the focal point is.
Answer: In front of the retina
◍ What ABO discrepancy category does a newborn most likely have?.
Answer: A newborn most likely has a 'Missing or weak antibody'
discrepancy.
◍ What is an appropriate resolution step for missing or weak antibody?.
Answer: An appropriate resolution step is to add more serum, up to 4 drops.
◍ What should be done if serum is limited during investigation of a missing or
weak antibody discrepancy?.
Answer: If serum is limited, it is recommended to use RESt adsorbed
plasma.
◍ Latent hyperboles and children especially need a ______________.
Answer: Cycloplegic refraction
◍ What is a cause of extra antigen in forward typing?.
Answer: A cause of extra antigen in forward typing is acquired B.
◍ Which of the following conditions could cause change in prescription in an
adult patient?.
Answer: Diabetes
STUDY GUIDE 2026 FULL QUESTIONS
AND SOLUTIONS GRADED A+
◍ An amsler's grid should be used on a daily basis for patients
with_____________.
Answer: Macular degeneration
◍ What is an ABO discrepancy?.
Answer: An ABO discrepancy is present when there is a disagreement
between Rh and ABO typing, forward and reverse typing, a positive
antibody screen, or a positive Direct Antiglobulin Test (DAT).
◍ Why must ABO discrepancies be resolved before transfusion?.
Answer: ABO discrepancies must be resolved before transfusion because
forward and reverse typing disagreement can lead to unsafe blood selection.
◍ Which of the following is used to check for lateral and vertical phorias.
Answer: Maddox rod
◍ What is one of the 4 major ABO discrepancy categories?.
Answer: One of the 4 major ABO discrepancy categories is 'Missing or
weak antigen.'
◍ A patient will experience photo phobia and Poor near vision
after____________.
Answer: Cycloplegic refraction
◍ If the patient says that the green side is clearer during the binocular
duochrome test, you should add_______O
U. .
Answer: Plus power
,◍ The physiologic blind spot is located where.
Answer: optic disk
◍ What is another major ABO discrepancy category?.
Answer: Another major ABO discrepancy category is 'Missing or weak
antibody.'
◍ What type of discrepancy would a very weak subgroup of A or B most
likely cause?.
Answer: A very weak subgroup of A or B would most likely cause a
'Missing or weak antigen' discrepancy.
◍ What is associated with loss of transferase in acute leukemia?.
Answer: Loss of transferase in acute leukemia is associated with 'missing or
weak antigen.'
◍ The near point of convergence is reached when the test object:.
Answer: Gets so close it blurs
◍ When measuring a patient with a horizontal deviation, the Maddox rod
should be positioned so that the line forms a__________.
Answer: Vertical line
◍ The instrument that provides information on the patient refractive status by
reflecting light off the retina is_____________.
Answer: Retniscope
◍ What may massive transfusion of group O blood cause?.
Answer: Massive transfusion of group O blood may cause a 'missing or
weak antibody discrepancy.'
◍ How may bone marrow transplant contribute to ABO discrepancies?.
Answer: Bone marrow transplant may contribute to both 'missing or weak
antigen' and 'missing or weak antibody' discrepancies.
◍ What is an appropriate resolution step for a missing or weak antigen
discrepancy?.
Answer: An appropriate resolution step is to incubate the front type at room
, temperature or 4-22°C for at least 15 minutes.
◍ Which reagent may react better with some weak A or B subgroups?.
Answer: Anti-A1 lectin may react better with some weak A or B subgroups.
◍ If a patient misses two letters on the 20/30 acuity line, the acuity should be
recorded as.
Answer: 20/30-2
◍ What is a cause of missing or weak antibody in reverse typing?.
Answer: A cause of missing or weak antibody in reverse typing is advanced
age.
◍ If the patient sees the red side clearer during a monocular duochrome test
the focal point is.
Answer: In front of the retina
◍ What ABO discrepancy category does a newborn most likely have?.
Answer: A newborn most likely has a 'Missing or weak antibody'
discrepancy.
◍ What is an appropriate resolution step for missing or weak antibody?.
Answer: An appropriate resolution step is to add more serum, up to 4 drops.
◍ What should be done if serum is limited during investigation of a missing or
weak antibody discrepancy?.
Answer: If serum is limited, it is recommended to use RESt adsorbed
plasma.
◍ Latent hyperboles and children especially need a ______________.
Answer: Cycloplegic refraction
◍ What is a cause of extra antigen in forward typing?.
Answer: A cause of extra antigen in forward typing is acquired B.
◍ Which of the following conditions could cause change in prescription in an
adult patient?.
Answer: Diabetes
