COMSAE PHASE 1 EXAM PREP 2026–2027 |
HIGH-YIELD PRACTICE QUESTIONS &
ANSWERS WITH DETAILED RATIONALES |
COMLEX LEVEL 1 READINESS STUDY GUIDE
• This 200-question practice exam mirrors the COMSAE Phase 1 / COMLEX Level 1
blueprint, covering all high-yield systems and disciplines tested on exam day.
• Use this material in timed blocks (25–50 questions per session), review every
EXPERT RATIONALE whether you got the question right or wrong, and revisit
missed topics in your primary resources before your next session.
COMSAE PHASE 1 EXAM PREP 2026–2027 HIGH-YIELD PRACTICE QUESTIONS &
ANSWERS WITH DETAILED EXPERT RATIONALE COMLEX LEVEL 1 READINESS
STUDY GUIDE
QUESTION 1 A 45-year-old man presents with crushing substernal chest pain
radiating to the left arm, diaphoresis, and nausea for the past 2 hours. ECG
shows 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
✔ CORRECT ANSWER: C. Right coronary artery
EXPERT RATIONALE: ST elevation in leads II, III, and aVF indicates an inferior
myocardial infarction. The right coronary artery (RCA) supplies the inferior wall of
the left ventricle in approximately 85% of individuals (right-dominant circulation).
Occlusion of the RCA is the most common cause of inferior STEMI.
,QUESTION 2 A 62-year-old woman with a history of hypertension presents
with sudden-onset severe headache described as "the worst headache of my
life." CT scan of the head is negative. What is the next best step?
A. MRI of the brain with gadolinium
B. Lumbar puncture
C. Cerebral angiography
D. Start sumatriptan
E. Administer IV nimodipine
✔ CORRECT ANSWER: B. Lumbar puncture
EXPERT RATIONALE: A thunderclap headache with a negative CT scan requires
lumbar puncture to rule out subarachnoid hemorrhage (SAH). CT has a sensitivity
of approximately 98% within the first 12 hours but decreases over time. LP will
show xanthochromia and elevated red blood cells in SAH.
QUESTION 3 A 3-year-old boy is brought in for evaluation of a neck mass.
Physical exam reveals a midline neck mass that moves with swallowing and
tongue protrusion. What is the most likely diagnosis?
A. Branchial cleft cyst
B. Cystic hygroma
C. Thyroglossal duct cyst
D. Dermoid cyst
E. Cervical lymphadenopathy
✔ CORRECT ANSWER: C. Thyroglossal duct cyst
EXPERT RATIONALE: A midline neck mass that moves with both swallowing and
tongue protrusion is pathognomonic for a thyroglossal duct cyst. It results from
failure of obliteration of the thyroglossal duct during thyroid descent. Treatment is
surgical excision (Sistrunk procedure).
,QUESTION 4 A 28-year-old woman presents at 10 weeks gestation with vaginal
bleeding and passage of grape-like vesicles. Beta-hCG is markedly elevated.
Ultrasound shows a "snowstorm" pattern with no fetal parts. What is the
most likely diagnosis?
A. Ectopic pregnancy
B. Threatened abortion
C. Complete hydatidiform mole
D. Partial hydatidiform mole
E. Choriocarcinoma
✔ CORRECT ANSWER: C. Complete hydatidiform mole
EXPERT RATIONALE: Complete hydatidiform mole results from fertilization of an
empty egg by one or two sperm (46,XX or 46,XY — all paternal). It presents with
markedly elevated beta-hCG, a "snowstorm" ultrasound pattern, and no fetal parts.
Management includes suction curettage and serial beta-hCG monitoring.
QUESTION 5 A 55-year-old man with a history of alcohol abuse presents with
confusion, ataxia, and ophthalmoplegia. What is the most appropriate
immediate treatment?
A. Glucose infusion
B. Thiamine (Vitamin B1)
C. Niacin (Vitamin B3)
D. Folate
E. Pyridoxine (Vitamin B6)
✔ CORRECT ANSWER: B. Thiamine (Vitamin B1)
EXPERT RATIONALE: This classic triad of confusion, ataxia, and ophthalmoplegia
represents Wernicke encephalopathy, caused by thiamine deficiency. Thiamine
, must be administered before glucose to avoid precipitating or worsening Wernicke
encephalopathy. Without treatment, it can progress to Korsakoff syndrome
(irreversible).
QUESTION 6 A 7-year-old boy presents with periorbital edema, frothy urine,
and hypoalbuminemia. Urinalysis shows 4+ proteinuria. Renal biopsy shows
normal light microscopy but effacement of podocyte foot processes on
electron microscopy. What is the most likely diagnosis?
A. Focal segmental glomerulosclerosis
B. Membranous nephropathy
C. Minimal change disease
D. IgA nephropathy
E. Membranoproliferative glomerulonephritis
✔ CORRECT ANSWER: C. Minimal change disease
EXPERT RATIONALE: Minimal change disease is the most common cause of
nephrotic syndrome in children. It is characterized by normal light microscopy,
negative immunofluorescence, and diffuse effacement of podocyte foot processes
on electron microscopy. It responds excellently to corticosteroids.
QUESTION 7 A 40-year-old woman presents with fatigue, weight gain, cold
intolerance, constipation, and dry skin. TSH is elevated and free T4 is low.
Anti-TPO antibodies are positive. What is the most likely diagnosis?
A. Graves disease
B. Subacute thyroiditis
C. Hashimoto thyroiditis
D. Secondary hypothyroidism
E. Sick euthyroid syndrome
HIGH-YIELD PRACTICE QUESTIONS &
ANSWERS WITH DETAILED RATIONALES |
COMLEX LEVEL 1 READINESS STUDY GUIDE
• This 200-question practice exam mirrors the COMSAE Phase 1 / COMLEX Level 1
blueprint, covering all high-yield systems and disciplines tested on exam day.
• Use this material in timed blocks (25–50 questions per session), review every
EXPERT RATIONALE whether you got the question right or wrong, and revisit
missed topics in your primary resources before your next session.
COMSAE PHASE 1 EXAM PREP 2026–2027 HIGH-YIELD PRACTICE QUESTIONS &
ANSWERS WITH DETAILED EXPERT RATIONALE COMLEX LEVEL 1 READINESS
STUDY GUIDE
QUESTION 1 A 45-year-old man presents with crushing substernal chest pain
radiating to the left arm, diaphoresis, and nausea for the past 2 hours. ECG
shows 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
✔ CORRECT ANSWER: C. Right coronary artery
EXPERT RATIONALE: ST elevation in leads II, III, and aVF indicates an inferior
myocardial infarction. The right coronary artery (RCA) supplies the inferior wall of
the left ventricle in approximately 85% of individuals (right-dominant circulation).
Occlusion of the RCA is the most common cause of inferior STEMI.
,QUESTION 2 A 62-year-old woman with a history of hypertension presents
with sudden-onset severe headache described as "the worst headache of my
life." CT scan of the head is negative. What is the next best step?
A. MRI of the brain with gadolinium
B. Lumbar puncture
C. Cerebral angiography
D. Start sumatriptan
E. Administer IV nimodipine
✔ CORRECT ANSWER: B. Lumbar puncture
EXPERT RATIONALE: A thunderclap headache with a negative CT scan requires
lumbar puncture to rule out subarachnoid hemorrhage (SAH). CT has a sensitivity
of approximately 98% within the first 12 hours but decreases over time. LP will
show xanthochromia and elevated red blood cells in SAH.
QUESTION 3 A 3-year-old boy is brought in for evaluation of a neck mass.
Physical exam reveals a midline neck mass that moves with swallowing and
tongue protrusion. What is the most likely diagnosis?
A. Branchial cleft cyst
B. Cystic hygroma
C. Thyroglossal duct cyst
D. Dermoid cyst
E. Cervical lymphadenopathy
✔ CORRECT ANSWER: C. Thyroglossal duct cyst
EXPERT RATIONALE: A midline neck mass that moves with both swallowing and
tongue protrusion is pathognomonic for a thyroglossal duct cyst. It results from
failure of obliteration of the thyroglossal duct during thyroid descent. Treatment is
surgical excision (Sistrunk procedure).
,QUESTION 4 A 28-year-old woman presents at 10 weeks gestation with vaginal
bleeding and passage of grape-like vesicles. Beta-hCG is markedly elevated.
Ultrasound shows a "snowstorm" pattern with no fetal parts. What is the
most likely diagnosis?
A. Ectopic pregnancy
B. Threatened abortion
C. Complete hydatidiform mole
D. Partial hydatidiform mole
E. Choriocarcinoma
✔ CORRECT ANSWER: C. Complete hydatidiform mole
EXPERT RATIONALE: Complete hydatidiform mole results from fertilization of an
empty egg by one or two sperm (46,XX or 46,XY — all paternal). It presents with
markedly elevated beta-hCG, a "snowstorm" ultrasound pattern, and no fetal parts.
Management includes suction curettage and serial beta-hCG monitoring.
QUESTION 5 A 55-year-old man with a history of alcohol abuse presents with
confusion, ataxia, and ophthalmoplegia. What is the most appropriate
immediate treatment?
A. Glucose infusion
B. Thiamine (Vitamin B1)
C. Niacin (Vitamin B3)
D. Folate
E. Pyridoxine (Vitamin B6)
✔ CORRECT ANSWER: B. Thiamine (Vitamin B1)
EXPERT RATIONALE: This classic triad of confusion, ataxia, and ophthalmoplegia
represents Wernicke encephalopathy, caused by thiamine deficiency. Thiamine
, must be administered before glucose to avoid precipitating or worsening Wernicke
encephalopathy. Without treatment, it can progress to Korsakoff syndrome
(irreversible).
QUESTION 6 A 7-year-old boy presents with periorbital edema, frothy urine,
and hypoalbuminemia. Urinalysis shows 4+ proteinuria. Renal biopsy shows
normal light microscopy but effacement of podocyte foot processes on
electron microscopy. What is the most likely diagnosis?
A. Focal segmental glomerulosclerosis
B. Membranous nephropathy
C. Minimal change disease
D. IgA nephropathy
E. Membranoproliferative glomerulonephritis
✔ CORRECT ANSWER: C. Minimal change disease
EXPERT RATIONALE: Minimal change disease is the most common cause of
nephrotic syndrome in children. It is characterized by normal light microscopy,
negative immunofluorescence, and diffuse effacement of podocyte foot processes
on electron microscopy. It responds excellently to corticosteroids.
QUESTION 7 A 40-year-old woman presents with fatigue, weight gain, cold
intolerance, constipation, and dry skin. TSH is elevated and free T4 is low.
Anti-TPO antibodies are positive. What is the most likely diagnosis?
A. Graves disease
B. Subacute thyroiditis
C. Hashimoto thyroiditis
D. Secondary hypothyroidism
E. Sick euthyroid syndrome
