COMLEX-USA Performance Evaluation
Preparation Assessment Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
Question 1
A 45-year-old man presents with sudden onset chest pain radiating to
the back. Blood pressure is 180/100 mmHg in the right arm and 150/90
mmHg in the left arm. What is the most likely diagnosis?
A. Myocardial infarction
B. Pulmonary embolism
C. Aortic dissection
D. Pericarditis
Answer: C. Aortic dissection
Rationale: Aortic dissection classically presents with sudden tearing
chest pain radiating to the back and unequal blood pressures between
arms due to involvement of branch vessels. This is a surgical
emergency requiring rapid imaging and blood pressure control.
,Question 2
A patient presents with fatigue, weight gain, cold intolerance, and
bradycardia. Which lab finding is most expected?
A. Low TSH, high T4
B. High TSH, low T4
C. Low TSH, low T4
D. High TSH, high T4
Answer: B. High TSH, low T4
Rationale: Primary hypothyroidism leads to decreased thyroid
hormone (T4), which triggers increased TSH due to loss of negative
feedback from the pituitary.
Question 3
A 60-year-old man with a history of smoking presents with hematuria.
What is the most likely diagnosis?
A. Renal cell carcinoma
B. Bladder cancer
C. Nephrolithiasis
D. Pyelonephritis
,Answer: B. Bladder cancer
Rationale: Painless hematuria in an older smoker strongly suggests
bladder transitional cell carcinoma due to carcinogen exposure.
Question 4
Which organism is most commonly associated with peptic ulcers in the
stomach and duodenum?
A. E. coli
B. Helicobacter pylori
C. Salmonella typhi
D. Clostridium difficile
Answer: B. Helicobacter pylori
Rationale: H. pylori is a gram-negative bacterium that damages
gastric mucosa and is a leading cause of peptic ulcer disease.
Question 5
A patient presents with drooping eyelid and diplopia that worsens
throughout the day. What is the most likely diagnosis?
A. Multiple sclerosis
B. Myasthenia gravis
, C. Guillain-Barré syndrome
D. Lambert-Eaton syndrome
Answer: B. Myasthenia gravis
Rationale: Myasthenia gravis is characterized by fatigable weakness
due to antibodies against acetylcholine receptors at the
neuromuscular junction.
Question 6
Which vitamin deficiency leads to night blindness?
A. Vitamin A
B. Vitamin B12
C. Vitamin C
D. Vitamin D
Answer: A. Vitamin A
Rationale: Vitamin A is essential for rhodopsin formation in the retina,
and deficiency leads to impaired night vision.
Question 7
A patient presents with severe watery diarrhea after antibiotic use.
What is the most likely pathogen?
Preparation Assessment Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
Question 1
A 45-year-old man presents with sudden onset chest pain radiating to
the back. Blood pressure is 180/100 mmHg in the right arm and 150/90
mmHg in the left arm. What is the most likely diagnosis?
A. Myocardial infarction
B. Pulmonary embolism
C. Aortic dissection
D. Pericarditis
Answer: C. Aortic dissection
Rationale: Aortic dissection classically presents with sudden tearing
chest pain radiating to the back and unequal blood pressures between
arms due to involvement of branch vessels. This is a surgical
emergency requiring rapid imaging and blood pressure control.
,Question 2
A patient presents with fatigue, weight gain, cold intolerance, and
bradycardia. Which lab finding is most expected?
A. Low TSH, high T4
B. High TSH, low T4
C. Low TSH, low T4
D. High TSH, high T4
Answer: B. High TSH, low T4
Rationale: Primary hypothyroidism leads to decreased thyroid
hormone (T4), which triggers increased TSH due to loss of negative
feedback from the pituitary.
Question 3
A 60-year-old man with a history of smoking presents with hematuria.
What is the most likely diagnosis?
A. Renal cell carcinoma
B. Bladder cancer
C. Nephrolithiasis
D. Pyelonephritis
,Answer: B. Bladder cancer
Rationale: Painless hematuria in an older smoker strongly suggests
bladder transitional cell carcinoma due to carcinogen exposure.
Question 4
Which organism is most commonly associated with peptic ulcers in the
stomach and duodenum?
A. E. coli
B. Helicobacter pylori
C. Salmonella typhi
D. Clostridium difficile
Answer: B. Helicobacter pylori
Rationale: H. pylori is a gram-negative bacterium that damages
gastric mucosa and is a leading cause of peptic ulcer disease.
Question 5
A patient presents with drooping eyelid and diplopia that worsens
throughout the day. What is the most likely diagnosis?
A. Multiple sclerosis
B. Myasthenia gravis
, C. Guillain-Barré syndrome
D. Lambert-Eaton syndrome
Answer: B. Myasthenia gravis
Rationale: Myasthenia gravis is characterized by fatigable weakness
due to antibodies against acetylcholine receptors at the
neuromuscular junction.
Question 6
Which vitamin deficiency leads to night blindness?
A. Vitamin A
B. Vitamin B12
C. Vitamin C
D. Vitamin D
Answer: A. Vitamin A
Rationale: Vitamin A is essential for rhodopsin formation in the retina,
and deficiency leads to impaired night vision.
Question 7
A patient presents with severe watery diarrhea after antibiotic use.
What is the most likely pathogen?
