COMSAE PHASE 1 ASA 113 FULL-
LENGTH REVIEW & PRACTICE
EXAMINATION QUESTIONS WITH
CORRECT ANSWERS PLUS
RATIONALES 2026/2027 EDITION
WITH INSTANT PDF DOWNLOAD
1. A 24-year-old woman presents with fatigue, weight loss, heat
intolerance, and palpitations. Examination shows a diffusely
enlarged thyroid and bilateral exophthalmos. Which mechanism
best explains her thyroid disease?
A. Destruction of thyroid follicles by cytotoxic T cells
B. Antibodies stimulating the thyroid-stimulating hormone
receptor
C. Antibodies blocking thyroid peroxidase
D. Excessive secretion of thyroid-stimulating hormone by a
pituitary adenoma
E. Autonomous secretion of thyroxine by thyroid carcinoma
Answer: B. Antibodies stimulating the thyroid-stimulating
hormone receptor
Rationale: Graves disease is caused by thyroid-stimulating
immunoglobulins that bind and activate the TSH receptor,
resulting in increased synthesis and release of thyroid hormones.
The diffuse goiter and ophthalmopathy are characteristic findings.
,2. A 67-year-old man with a history of smoking develops
progressive painless hematuria. Cystoscopy reveals a papillary
bladder mass. Which histologic finding is most likely?
A. Keratin pearls
B. Gland formation
C. Urothelial cells with atypia
D. Reed-Sternberg cells
E. Signet-ring cells
Answer: C. Urothelial cells with atypia
Rationale: Most smoking-associated bladder malignancies are
urothelial carcinomas. They commonly present with painless
gross hematuria and arise from the transitional epithelium lining
the urinary tract.
3. A 58-year-old man develops sudden crushing substernal chest
pain radiating to his left arm. ECG demonstrates ST-segment
elevation in leads II, III, and aVF. Which coronary artery is most
likely occluded?
A. Left anterior descending artery
B. Left circumflex artery
C. Right coronary artery
D. Left main coronary artery
E. Posterior descending artery
Answer: C. Right coronary artery
Rationale: ST elevation in leads II, III, and aVF indicates an inferior
myocardial infarction. The right coronary artery is the most
common vessel responsible for inferior-wall infarction.
,4. A 35-year-old woman develops proximal muscle weakness and
difficulty climbing stairs. Laboratory testing shows elevated
creatine kinase. She has a heliotrope rash and Gottron papules.
Which diagnosis is most likely?
A. Polymyalgia rheumatica
B. Dermatomyositis
C. Myasthenia gravis
D. Systemic sclerosis
E. Rheumatoid arthritis
Answer: B. Dermatomyositis
Rationale: Dermatomyositis produces symmetric proximal
muscle weakness accompanied by characteristic cutaneous
findings, including heliotrope rash and Gottron papules. Muscle
inflammation causes elevated creatine kinase.
5. A patient develops profuse watery diarrhea after receiving
clindamycin. Colonoscopy shows yellow-white plaques overlying
the colonic mucosa. Which organism is responsible?
A. Escherichia coli
B. Campylobacter jejuni
C. Clostridioides difficile
D. Salmonella enterica
E. Shigella dysenteriae
Answer: C. Clostridioides difficile
Rationale: Antibiotic exposure, particularly with clindamycin,
predisposes to C. difficile overgrowth. Its toxins cause
, pseudomembranous colitis characterized by watery diarrhea and
yellow-white mucosal plaques.
6. A 42-year-old woman has episodic severe headaches,
diaphoresis, palpitations, and hypertension. A tumor of the
adrenal medulla is suspected. Which substance is most likely
elevated?
A. Aldosterone
B. Cortisol
C. Epinephrine and norepinephrine
D. Renin
E. Angiotensin II
Answer: C. Epinephrine and norepinephrine
Rationale: Pheochromocytomas arise from chromaffin cells of the
adrenal medulla and secrete catecholamines. Episodic
headache, sweating, palpitations, and hypertension are classic
manifestations.
7. A 9-year-old boy develops periorbital edema and cola-colored
urine two weeks after an untreated throat infection. Which
laboratory finding is most likely?
A. Increased serum C3
B. Decreased serum C3
C. Positive anti-CCP antibody
D. Increased serum IgE
E. Positive anti-mitochondrial antibody
Answer: B. Decreased serum C3
LENGTH REVIEW & PRACTICE
EXAMINATION QUESTIONS WITH
CORRECT ANSWERS PLUS
RATIONALES 2026/2027 EDITION
WITH INSTANT PDF DOWNLOAD
1. A 24-year-old woman presents with fatigue, weight loss, heat
intolerance, and palpitations. Examination shows a diffusely
enlarged thyroid and bilateral exophthalmos. Which mechanism
best explains her thyroid disease?
A. Destruction of thyroid follicles by cytotoxic T cells
B. Antibodies stimulating the thyroid-stimulating hormone
receptor
C. Antibodies blocking thyroid peroxidase
D. Excessive secretion of thyroid-stimulating hormone by a
pituitary adenoma
E. Autonomous secretion of thyroxine by thyroid carcinoma
Answer: B. Antibodies stimulating the thyroid-stimulating
hormone receptor
Rationale: Graves disease is caused by thyroid-stimulating
immunoglobulins that bind and activate the TSH receptor,
resulting in increased synthesis and release of thyroid hormones.
The diffuse goiter and ophthalmopathy are characteristic findings.
,2. A 67-year-old man with a history of smoking develops
progressive painless hematuria. Cystoscopy reveals a papillary
bladder mass. Which histologic finding is most likely?
A. Keratin pearls
B. Gland formation
C. Urothelial cells with atypia
D. Reed-Sternberg cells
E. Signet-ring cells
Answer: C. Urothelial cells with atypia
Rationale: Most smoking-associated bladder malignancies are
urothelial carcinomas. They commonly present with painless
gross hematuria and arise from the transitional epithelium lining
the urinary tract.
3. A 58-year-old man develops sudden crushing substernal chest
pain radiating to his left arm. ECG demonstrates ST-segment
elevation in leads II, III, and aVF. Which coronary artery is most
likely occluded?
A. Left anterior descending artery
B. Left circumflex artery
C. Right coronary artery
D. Left main coronary artery
E. Posterior descending artery
Answer: C. Right coronary artery
Rationale: ST elevation in leads II, III, and aVF indicates an inferior
myocardial infarction. The right coronary artery is the most
common vessel responsible for inferior-wall infarction.
,4. A 35-year-old woman develops proximal muscle weakness and
difficulty climbing stairs. Laboratory testing shows elevated
creatine kinase. She has a heliotrope rash and Gottron papules.
Which diagnosis is most likely?
A. Polymyalgia rheumatica
B. Dermatomyositis
C. Myasthenia gravis
D. Systemic sclerosis
E. Rheumatoid arthritis
Answer: B. Dermatomyositis
Rationale: Dermatomyositis produces symmetric proximal
muscle weakness accompanied by characteristic cutaneous
findings, including heliotrope rash and Gottron papules. Muscle
inflammation causes elevated creatine kinase.
5. A patient develops profuse watery diarrhea after receiving
clindamycin. Colonoscopy shows yellow-white plaques overlying
the colonic mucosa. Which organism is responsible?
A. Escherichia coli
B. Campylobacter jejuni
C. Clostridioides difficile
D. Salmonella enterica
E. Shigella dysenteriae
Answer: C. Clostridioides difficile
Rationale: Antibiotic exposure, particularly with clindamycin,
predisposes to C. difficile overgrowth. Its toxins cause
, pseudomembranous colitis characterized by watery diarrhea and
yellow-white mucosal plaques.
6. A 42-year-old woman has episodic severe headaches,
diaphoresis, palpitations, and hypertension. A tumor of the
adrenal medulla is suspected. Which substance is most likely
elevated?
A. Aldosterone
B. Cortisol
C. Epinephrine and norepinephrine
D. Renin
E. Angiotensin II
Answer: C. Epinephrine and norepinephrine
Rationale: Pheochromocytomas arise from chromaffin cells of the
adrenal medulla and secrete catecholamines. Episodic
headache, sweating, palpitations, and hypertension are classic
manifestations.
7. A 9-year-old boy develops periorbital edema and cola-colored
urine two weeks after an untreated throat infection. Which
laboratory finding is most likely?
A. Increased serum C3
B. Decreased serum C3
C. Positive anti-CCP antibody
D. Increased serum IgE
E. Positive anti-mitochondrial antibody
Answer: B. Decreased serum C3
