STEP 2CK CERTIFICATION PAPER 2026
FULL SOLUTION GRADED A+
● A 73-year-old woman comes with decreased position and vibratory
sensation of the lower extremities, a hematocrit of 28%, MCV of 114 fL,
and hypersegmented neutrophils. Her B12 level is decreased, but near
the borderline of normal. What is the most appropriate next step in the
management of this patient?
A. Methylmalonic acid level
B. Anti-intrinsic factor antibodies
C. Anti-parietal cell antibodies
D. Schillings test
E. Folate level
F. Homocysteine level Answer: Answer: A. USMLE Step 2 CK
frequently tests the fact that while both B12 and folate deficiency
increase homocysteine levels, only B12 is associated with an increased
MMA. The B12 level can be normal in as many as a third of patients
with B12 deficiency because the carrier protein, transcobalamin, is an
acute phase reactant and can be elevated from many forms of stress such
as infection, cancer, or trauma. When the story suggests B12 deficiency
and the B12 level is equivocal, use an increased MMA level to confirm
the diagnosis of vitamin B12 deficiency.
● Which of the following is a complication of B12 or folate
replacement?
, A. Seizures
B. Hemolysis
C. Hypokalemia
D. Hyperkalemia
E. Diarrhea Answer: Answer: C. Extremely rapid cell production in the
bone marrow causes hypokalemia. There is no other condition in which
cells are generated so rapidly that they use up all the potassium.
Hyperkalemia from massive tissue or cellular breakdown has many
causes. Hypokalemia from cell production is rare. When replacing B12
and folate, particularly if there is pancytopenia, cells in the marrow are
produced so rapidly that the marrow packages up all the potassium,
lowering the serum level. Observe and replace.
● Which of the following can be found on smear in sickle cell disease?
A. Basophilic stippling
B. Howell-Jolly bodies
C. Bite cells
D. Schistocytes
E. Morulae Answer: Answer: B. These are precipitated remnants of
nuclear material seen inside the red cells of a patient who does not have
a spleen. There is no change in therapy or management based on the
presence of Howell-Jolly bodies. Basophilic stippling is associated with
a number of causes of sideroblastic anemia, especially lead poisoning.
Bite cells are seen in glucose-6-phosphate-dehydrogenase deficiency.
Schistocytes are fragmented red cells seen with intravascular hemolysis.
Morulae are seen inside neutrophils in Ehrlichia infections.
FULL SOLUTION GRADED A+
● A 73-year-old woman comes with decreased position and vibratory
sensation of the lower extremities, a hematocrit of 28%, MCV of 114 fL,
and hypersegmented neutrophils. Her B12 level is decreased, but near
the borderline of normal. What is the most appropriate next step in the
management of this patient?
A. Methylmalonic acid level
B. Anti-intrinsic factor antibodies
C. Anti-parietal cell antibodies
D. Schillings test
E. Folate level
F. Homocysteine level Answer: Answer: A. USMLE Step 2 CK
frequently tests the fact that while both B12 and folate deficiency
increase homocysteine levels, only B12 is associated with an increased
MMA. The B12 level can be normal in as many as a third of patients
with B12 deficiency because the carrier protein, transcobalamin, is an
acute phase reactant and can be elevated from many forms of stress such
as infection, cancer, or trauma. When the story suggests B12 deficiency
and the B12 level is equivocal, use an increased MMA level to confirm
the diagnosis of vitamin B12 deficiency.
● Which of the following is a complication of B12 or folate
replacement?
, A. Seizures
B. Hemolysis
C. Hypokalemia
D. Hyperkalemia
E. Diarrhea Answer: Answer: C. Extremely rapid cell production in the
bone marrow causes hypokalemia. There is no other condition in which
cells are generated so rapidly that they use up all the potassium.
Hyperkalemia from massive tissue or cellular breakdown has many
causes. Hypokalemia from cell production is rare. When replacing B12
and folate, particularly if there is pancytopenia, cells in the marrow are
produced so rapidly that the marrow packages up all the potassium,
lowering the serum level. Observe and replace.
● Which of the following can be found on smear in sickle cell disease?
A. Basophilic stippling
B. Howell-Jolly bodies
C. Bite cells
D. Schistocytes
E. Morulae Answer: Answer: B. These are precipitated remnants of
nuclear material seen inside the red cells of a patient who does not have
a spleen. There is no change in therapy or management based on the
presence of Howell-Jolly bodies. Basophilic stippling is associated with
a number of causes of sideroblastic anemia, especially lead poisoning.
Bite cells are seen in glucose-6-phosphate-dehydrogenase deficiency.
Schistocytes are fragmented red cells seen with intravascular hemolysis.
Morulae are seen inside neutrophils in Ehrlichia infections.
