COMSAE LEVEL 1 FORM A PRACTICE TEST QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF
Core Domains
- Foundational Biomedical Sciences
*- Osteopathic Principles and Practice*
*- Systems-Based Clinical Presentations*
*- Diagnostic Reasoning and Interpretation*
*- Pharmacology and Therapeutics*
*- Professionalism, Ethics, and Communication*
*- Public Health and Preventive Medicine*
*- Clinical Decision-Making and Management*
Introduction
This practice test simulates a comprehensive assessment designed to evaluate candidates’ mastery of
foundational biomedical science, clinical reasoning, and osteopathic principles.
It assesses knowledge across multiple disciplines, skills in diagnostic interpretation, and the ability to apply
clinical concepts to patient presentations.
The format consists of single-best-answer multiple-choice items and scenario-based questions that require
integration of basic science with clinical decision-making.
Items emphasize real-world application, patient-centered judgment, and professionalism to prepare
examinees for high-stakes licensure-style testing.
Section One: Questions 1–100
,. A 55-year-old man presents with progressive exertional dyspnea and orthopnea; exam shows bibasilar crackles
and an S3 heart sound. Which mechanism best explains his symptoms?
A. Decreased left ventricular ejection fraction leading to increased left atrial pressure
B. Pulmonary arterial vasoconstriction from hypoxia
C. Isolated right ventricular infarction causing systemic venous congestion
D. Primary pulmonary parenchymal fibrosis decreasing diffusion capacity
🟢 A. Decreased left ventricular ejection fraction leading to increased left atrial pressure
🔴 RATIONALE: S3 and pulmonary edema with orthopnea are classic for left ventricular systolic dysfunction
causing elevated left-sided filling pressures and pulmonary venous congestion.
. Which antibiotic’s mechanism is inhibition of the 50S ribosomal subunit peptidyl transferase?
A. Gentamicin
B. Clarithromycin
C. Linezolid
D. Tetracycline
🟢 C. Linezolid
🔴 RATIONALE: Linezolid inhibits initiation and peptidyl transferase on the 50S subunit; macrolides
(clarithromycin) bind 50S at a different site but linezolid is the prototypical peptidyl transferase inhibitor.
. A patient with poorly controlled type 1 diabetes develops polyuria, polydipsia, and fruity breath. Which lab
abnormality is most consistent?
A. Low anion gap with metabolic alkalosis
B. High anion gap metabolic acidosis with elevated β-hydroxybutyrate
C. Normal anion gap metabolic acidosis with hyperchloremia
D. Respiratory alkalosis with low PaCO2
🟢 B. High anion gap metabolic acidosis with elevated β-hydroxybutyrate
🔴 RATIONALE: Diabetic ketoacidosis produces high anion gap metabolic acidosis due to accumulation of
ketone bodies like β-hydroxybutyrate, causing fruity breath.
,. Which bone lesion is characteristically lytic with “soap-bubble” appearance and often occurs around the knee
in young adults?
A. Osteoid osteoma
B. Giant cell tumor
C. Osteosarcoma
D. Enchondroma
🟢 B. Giant cell tumor
🔴 RATIONALE: Giant cell tumors typically present in epiphyses of long bones in young adults with lytic,
soap-bubble radiographic appearance.
. A 30-year-old woman presents with heat intolerance, weight loss, and tremor; lab shows suppressed TSH and
elevated free T4. Which is the most specific next step to determine etiology?
A. Radioactive iodine uptake scan
B. Thyroid ultrasound
C. Measurement of anti-thyroid peroxidase antibodies
D. TSH-receptor antibody assay
🟢 D. TSH-receptor antibody assay
🔴 RATIONALE: A suppressed TSH with elevated T4 suggests hyperthyroidism; TSH-receptor antibodies
identify Graves disease specifically, which guides management.
. Which heart valve abnormality most commonly produces holosystolic murmur heard best at the apex radiating
to the axilla?
A. Aortic stenosis
B. Mitral regurgitation
C. Tricuspid stenosis
D. Pulmonic regurgitation
🟢 B. Mitral regurgitation
🔴 RATIONALE: Mitral regurgitation produces a holosystolic murmur loudest at the apex, often radiating to
the left axilla due to backflow into the left atrium during systole.
, . A 65-year-old smoker with hematuria and left flank pain; CT shows a solid renal mass. What is the most likely
diagnosis?
A. Renal cell carcinoma
B. Transitional cell carcinoma of the bladder
C. Simple renal cyst
D. Pyelonephritis
🟢 A. Renal cell carcinoma
🔴 RATIONALE: Solid renal masses in older smokers with hematuria are most suspicious for renal cell
carcinoma arising from renal tubular epithelium.
. Which neurotransmitter deficiency is most associated with major depressive disorder pathophysiology
theories?
A. Dopamine only
B. Serotonin and norepinephrine
C. GABA and glycine
D. Acetylcholine exclusively
🟢 B. Serotonin and norepinephrine
🔴 RATIONALE: Monoamine hypotheses of depression emphasize reduced serotonergic and noradrenergic
neurotransmission as central contributors.
. In osteopathic manipulative treatment, a direct high-velocity, low-amplitude thrust primarily aims to:
A. Increase range of motion by overcoming restrictive barrier
B. Strengthen antagonist muscles through isometric contraction
C. Replace joint cartilage through traction
D. Activate systemic endocrine response exclusively
🟢 A. Increase range of motion by overcoming restrictive barrier
🔴 RATIONALE: HVLA thrusts are directed to the restrictive barrier to restore motion; they act locally on
joint mechanics, not to replace cartilage or primarily modulate endocrine function.
(VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF
Core Domains
- Foundational Biomedical Sciences
*- Osteopathic Principles and Practice*
*- Systems-Based Clinical Presentations*
*- Diagnostic Reasoning and Interpretation*
*- Pharmacology and Therapeutics*
*- Professionalism, Ethics, and Communication*
*- Public Health and Preventive Medicine*
*- Clinical Decision-Making and Management*
Introduction
This practice test simulates a comprehensive assessment designed to evaluate candidates’ mastery of
foundational biomedical science, clinical reasoning, and osteopathic principles.
It assesses knowledge across multiple disciplines, skills in diagnostic interpretation, and the ability to apply
clinical concepts to patient presentations.
The format consists of single-best-answer multiple-choice items and scenario-based questions that require
integration of basic science with clinical decision-making.
Items emphasize real-world application, patient-centered judgment, and professionalism to prepare
examinees for high-stakes licensure-style testing.
Section One: Questions 1–100
,. A 55-year-old man presents with progressive exertional dyspnea and orthopnea; exam shows bibasilar crackles
and an S3 heart sound. Which mechanism best explains his symptoms?
A. Decreased left ventricular ejection fraction leading to increased left atrial pressure
B. Pulmonary arterial vasoconstriction from hypoxia
C. Isolated right ventricular infarction causing systemic venous congestion
D. Primary pulmonary parenchymal fibrosis decreasing diffusion capacity
🟢 A. Decreased left ventricular ejection fraction leading to increased left atrial pressure
🔴 RATIONALE: S3 and pulmonary edema with orthopnea are classic for left ventricular systolic dysfunction
causing elevated left-sided filling pressures and pulmonary venous congestion.
. Which antibiotic’s mechanism is inhibition of the 50S ribosomal subunit peptidyl transferase?
A. Gentamicin
B. Clarithromycin
C. Linezolid
D. Tetracycline
🟢 C. Linezolid
🔴 RATIONALE: Linezolid inhibits initiation and peptidyl transferase on the 50S subunit; macrolides
(clarithromycin) bind 50S at a different site but linezolid is the prototypical peptidyl transferase inhibitor.
. A patient with poorly controlled type 1 diabetes develops polyuria, polydipsia, and fruity breath. Which lab
abnormality is most consistent?
A. Low anion gap with metabolic alkalosis
B. High anion gap metabolic acidosis with elevated β-hydroxybutyrate
C. Normal anion gap metabolic acidosis with hyperchloremia
D. Respiratory alkalosis with low PaCO2
🟢 B. High anion gap metabolic acidosis with elevated β-hydroxybutyrate
🔴 RATIONALE: Diabetic ketoacidosis produces high anion gap metabolic acidosis due to accumulation of
ketone bodies like β-hydroxybutyrate, causing fruity breath.
,. Which bone lesion is characteristically lytic with “soap-bubble” appearance and often occurs around the knee
in young adults?
A. Osteoid osteoma
B. Giant cell tumor
C. Osteosarcoma
D. Enchondroma
🟢 B. Giant cell tumor
🔴 RATIONALE: Giant cell tumors typically present in epiphyses of long bones in young adults with lytic,
soap-bubble radiographic appearance.
. A 30-year-old woman presents with heat intolerance, weight loss, and tremor; lab shows suppressed TSH and
elevated free T4. Which is the most specific next step to determine etiology?
A. Radioactive iodine uptake scan
B. Thyroid ultrasound
C. Measurement of anti-thyroid peroxidase antibodies
D. TSH-receptor antibody assay
🟢 D. TSH-receptor antibody assay
🔴 RATIONALE: A suppressed TSH with elevated T4 suggests hyperthyroidism; TSH-receptor antibodies
identify Graves disease specifically, which guides management.
. Which heart valve abnormality most commonly produces holosystolic murmur heard best at the apex radiating
to the axilla?
A. Aortic stenosis
B. Mitral regurgitation
C. Tricuspid stenosis
D. Pulmonic regurgitation
🟢 B. Mitral regurgitation
🔴 RATIONALE: Mitral regurgitation produces a holosystolic murmur loudest at the apex, often radiating to
the left axilla due to backflow into the left atrium during systole.
, . A 65-year-old smoker with hematuria and left flank pain; CT shows a solid renal mass. What is the most likely
diagnosis?
A. Renal cell carcinoma
B. Transitional cell carcinoma of the bladder
C. Simple renal cyst
D. Pyelonephritis
🟢 A. Renal cell carcinoma
🔴 RATIONALE: Solid renal masses in older smokers with hematuria are most suspicious for renal cell
carcinoma arising from renal tubular epithelium.
. Which neurotransmitter deficiency is most associated with major depressive disorder pathophysiology
theories?
A. Dopamine only
B. Serotonin and norepinephrine
C. GABA and glycine
D. Acetylcholine exclusively
🟢 B. Serotonin and norepinephrine
🔴 RATIONALE: Monoamine hypotheses of depression emphasize reduced serotonergic and noradrenergic
neurotransmission as central contributors.
. In osteopathic manipulative treatment, a direct high-velocity, low-amplitude thrust primarily aims to:
A. Increase range of motion by overcoming restrictive barrier
B. Strengthen antagonist muscles through isometric contraction
C. Replace joint cartilage through traction
D. Activate systemic endocrine response exclusively
🟢 A. Increase range of motion by overcoming restrictive barrier
🔴 RATIONALE: HVLA thrusts are directed to the restrictive barrier to restore motion; they act locally on
joint mechanics, not to replace cartilage or primarily modulate endocrine function.
