COMSAE Level 1 (Form A) practice exam
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026
Q&A | INSTANT DOWNLOAD PDF
1. A 62-year-old man with a 40 pack-year smoking history presents
with hemoptysis and weight loss. Chest x-ray shows a central hilar
mass. Which paraneoplastic syndrome is most commonly
associated with a central lung tumor (squamous cell carcinoma)?
A. SIADH
B. Cushing syndrome
C. Hypercalcemia
D. Lambert-Eaton myasthenic syndrome
Hypercalcemia from PTHrP is classically associated with
squamous cell carcinoma of the lung, a central tumor.
2. Which vitamin deficiency causes impaired wound healing and
bleeding gums due to defective collagen synthesis?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Vitamin C (ascorbic acid) is required for hydroxylation of
proline/lysine in collagen; deficiency → scurvy with poor wound
healing and bleeding gums.
3. A 24-year-old woman has recurrent sinusitis and otitis media; she
has situs inversus and chronic productive cough. Which pathogen
is most likely causing her infections?
, A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Pseudomonas aeruginosa
D. Staphylococcus aureus
Patients with primary ciliary dyskinesia (Kartagener syndrome)
commonly have chronic respiratory infections; Pseudomonas
frequently colonizes damaged airways.
4. Which antibiotic is bactericidal and works by inhibiting bacterial
cell wall synthesis via binding to PBPs?
A. Tetracycline
B. Chloramphenicol
C. Penicillin G
D. Erythromycin
Penicillin G is bactericidal and inhibits peptidoglycan cross-
linking by binding penicillin-binding proteins.
5. A 55-year-old man with long-standing GERD develops dysphagia.
Endoscopy shows Barrett esophagus. Which histologic change
characterizes Barrett esophagus?
A. Squamous epithelium with dysplasia
B. Columnar epithelium with goblet cells (intestinal metaplasia)
C. Keratinized stratified squamous epithelium
D. Pseudostratified ciliated columnar epithelium
Barrett esophagus is replacement of normal stratified squamous
epithelium with intestinal-type columnar epithelium with goblet
cells due to chronic GERD.
6. Which electrolyte abnormality is most likely to cause peaked T
waves on ECG?
A. Hypocalcemia
B. Hyponatremia
, C. Hypokalemia
D. Hyperkalemia
Hyperkalemia causes peaked T waves, widened QRS, and can
progress to sine-wave pattern and ventricular fibrillation.
7. A 3-year-old boy with high fever and a “strawberry” tongue has
skin rash and conjunctival injection. The major complication to
watch for is:
A. Renal failure
B. Pulmonary fibrosis
C. Coronary artery aneurysms
D. Cerebral aneurysm
Kawasaki disease causes medium-vessel vasculitis and can lead
to coronary artery aneurysms if untreated.
8. Which of the following enzymes is the rate-limiting step of
glycolysis?
A. Hexokinase
B. Pyruvate kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
PFK-1 catalyzes fructose-6-phosphate → fructose-1,6-
bisphosphate and is the major regulatory, rate-limiting enzyme
of glycolysis.
9. A patient with long-term use of a loop diuretic develops metabolic
alkalosis and hypokalemia. Which mechanism explains the
metabolic alkalosis?
A. Increased H+ secretion in distal tubule due to volume depletion
and increased aldosterone
B. Direct inhibition of carbonic anhydrase
C. Increased bicarbonate reabsorption from proximal tubule due
, to hypernatremia
D. Increased distal H+ secretion from aldosterone-mediated H+
secretion and volume contraction
Loop diuretics cause volume contraction and stimulate RAAS →
aldosterone increases distal H+ secretion and HCO₃⁻ retention,
producing metabolic alkalosis.
10. A neonate presents with jaundice in the first 24 hours of life
and is found to have blood group incompatibility. The mechanism
is:
A. IgM-mediated hemolysis across placenta
B. IgG-mediated hemolysis crossing placenta
C. Complement activation by IgA
D. Direct biliary obstruction
Maternal IgG antibodies cross the placenta and cause hemolysis
of fetal RBCs in hemolytic disease of the newborn due to blood
group incompatibility.
11. OMM: A patient presents with acute right lower quadrant
abdominal pain. Which Chapman’s point correlates with the
appendix?
A. Left anterior superior pubic ramus
B. Tip of the right 12th rib and right T12-L1 transverse process
C. Midline L4 spinous process
D. Left posterior inferior occiput
Chapman’s reflexes for the appendix commonly localize to the
tip of the right 12th rib anteriorly and corresponding posterior
points near T12-L1.
12. Which receptor is Gs-coupled and increases intracellular
cAMP when activated?
A. α2-adrenergic receptor
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026
Q&A | INSTANT DOWNLOAD PDF
1. A 62-year-old man with a 40 pack-year smoking history presents
with hemoptysis and weight loss. Chest x-ray shows a central hilar
mass. Which paraneoplastic syndrome is most commonly
associated with a central lung tumor (squamous cell carcinoma)?
A. SIADH
B. Cushing syndrome
C. Hypercalcemia
D. Lambert-Eaton myasthenic syndrome
Hypercalcemia from PTHrP is classically associated with
squamous cell carcinoma of the lung, a central tumor.
2. Which vitamin deficiency causes impaired wound healing and
bleeding gums due to defective collagen synthesis?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Vitamin C (ascorbic acid) is required for hydroxylation of
proline/lysine in collagen; deficiency → scurvy with poor wound
healing and bleeding gums.
3. A 24-year-old woman has recurrent sinusitis and otitis media; she
has situs inversus and chronic productive cough. Which pathogen
is most likely causing her infections?
, A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Pseudomonas aeruginosa
D. Staphylococcus aureus
Patients with primary ciliary dyskinesia (Kartagener syndrome)
commonly have chronic respiratory infections; Pseudomonas
frequently colonizes damaged airways.
4. Which antibiotic is bactericidal and works by inhibiting bacterial
cell wall synthesis via binding to PBPs?
A. Tetracycline
B. Chloramphenicol
C. Penicillin G
D. Erythromycin
Penicillin G is bactericidal and inhibits peptidoglycan cross-
linking by binding penicillin-binding proteins.
5. A 55-year-old man with long-standing GERD develops dysphagia.
Endoscopy shows Barrett esophagus. Which histologic change
characterizes Barrett esophagus?
A. Squamous epithelium with dysplasia
B. Columnar epithelium with goblet cells (intestinal metaplasia)
C. Keratinized stratified squamous epithelium
D. Pseudostratified ciliated columnar epithelium
Barrett esophagus is replacement of normal stratified squamous
epithelium with intestinal-type columnar epithelium with goblet
cells due to chronic GERD.
6. Which electrolyte abnormality is most likely to cause peaked T
waves on ECG?
A. Hypocalcemia
B. Hyponatremia
, C. Hypokalemia
D. Hyperkalemia
Hyperkalemia causes peaked T waves, widened QRS, and can
progress to sine-wave pattern and ventricular fibrillation.
7. A 3-year-old boy with high fever and a “strawberry” tongue has
skin rash and conjunctival injection. The major complication to
watch for is:
A. Renal failure
B. Pulmonary fibrosis
C. Coronary artery aneurysms
D. Cerebral aneurysm
Kawasaki disease causes medium-vessel vasculitis and can lead
to coronary artery aneurysms if untreated.
8. Which of the following enzymes is the rate-limiting step of
glycolysis?
A. Hexokinase
B. Pyruvate kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
PFK-1 catalyzes fructose-6-phosphate → fructose-1,6-
bisphosphate and is the major regulatory, rate-limiting enzyme
of glycolysis.
9. A patient with long-term use of a loop diuretic develops metabolic
alkalosis and hypokalemia. Which mechanism explains the
metabolic alkalosis?
A. Increased H+ secretion in distal tubule due to volume depletion
and increased aldosterone
B. Direct inhibition of carbonic anhydrase
C. Increased bicarbonate reabsorption from proximal tubule due
, to hypernatremia
D. Increased distal H+ secretion from aldosterone-mediated H+
secretion and volume contraction
Loop diuretics cause volume contraction and stimulate RAAS →
aldosterone increases distal H+ secretion and HCO₃⁻ retention,
producing metabolic alkalosis.
10. A neonate presents with jaundice in the first 24 hours of life
and is found to have blood group incompatibility. The mechanism
is:
A. IgM-mediated hemolysis across placenta
B. IgG-mediated hemolysis crossing placenta
C. Complement activation by IgA
D. Direct biliary obstruction
Maternal IgG antibodies cross the placenta and cause hemolysis
of fetal RBCs in hemolytic disease of the newborn due to blood
group incompatibility.
11. OMM: A patient presents with acute right lower quadrant
abdominal pain. Which Chapman’s point correlates with the
appendix?
A. Left anterior superior pubic ramus
B. Tip of the right 12th rib and right T12-L1 transverse process
C. Midline L4 spinous process
D. Left posterior inferior occiput
Chapman’s reflexes for the appendix commonly localize to the
tip of the right 12th rib anteriorly and corresponding posterior
points near T12-L1.
12. Which receptor is Gs-coupled and increases intracellular
cAMP when activated?
A. α2-adrenergic receptor
