COMSAE Phase 1–Style Practice Questions and Answers
2025-2026
✅ Original COMSAE/COMLEX-style clinical vignette questions
✅ Multiple-choice answers (A–E)
✅ Correct answer
✅ Detailed rationale
✅ High-yield review pearls
Question 1 – Cardiovascular Physiology
A 65-year-old man presents with crushing substernal chest pain radiating to his left arm. An 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 wall myocardial infarction, most commonly
caused by occlusion of the right coronary artery (RCA).
High-Yield Pearl: Inferior MI → II, III, aVF → RCA.
Question 2 – Microbiology
A 22-year-old college student develops fever, headache, neck stiffness, and a petechial rash.
Cerebrospinal fluid culture grows gram-negative diplococci.
Which organism is most likely responsible?
A. Haemophilus influenzae
B. Neisseria meningitidis
C. Listeria monocytogenes
D. Streptococcus pneumoniae
E. Escherichia coli
✅ Answer: B. Neisseria meningitidis
Rationale
,The combination of meningitis and a petechial rash is classic for Neisseria meningitidis, a gram-
negative diplococcus.
High-Yield Pearl: Meningococcal disease can progress rapidly to septic shock and disseminated
intravascular coagulation.
Question 3 – Pharmacology
A patient with hypertension and diabetes has persistent microalbuminuria. Which medication
provides both blood pressure control and renal protection?
A. Hydrochlorothiazide
B. Metoprolol
C. Lisinopril
D. Amlodipine
E. Clonidine
✅ Answer: C. Lisinopril
Rationale
ACE inhibitors reduce intraglomerular pressure, decrease proteinuria, and help slow diabetic kidney
disease progression.
Question 4 – Pathology
A patient with long-standing gastroesophageal reflux develops intestinal metaplasia of the distal
esophagus.
This condition is called:
A. Achalasia
B. Barrett esophagus
C. Esophageal varices
D. Zenker diverticulum
E. Mallory-Weiss syndrome
✅ Answer: B. Barrett esophagus
Rationale
Chronic acid exposure causes replacement of normal squamous epithelium with intestinal-type
columnar epithelium, increasing the risk of esophageal adenocarcinoma.
Question 5 – Biochemistry
,A child presents with developmental delay and a musty body odor. Deficiency of which enzyme is
responsible?
A. Phenylalanine hydroxylase
B. Tyrosinase
C. Homogentisate oxidase
D. Branched-chain α-ketoacid dehydrogenase
E. Galactose-1-phosphate uridyltransferase
✅ Answer: A. Phenylalanine hydroxylase
Rationale
Phenylketonuria (PKU) results from deficiency of phenylalanine hydroxylase, causing accumulation of
phenylalanine.
Question 6 – Physiology
Which portion of the nephron reabsorbs the greatest percentage of filtered sodium?
A. Distal convoluted tubule
B. Collecting duct
C. Thick ascending limb
D. Proximal convoluted tubule
E. Thin descending limb
✅ Answer: D. Proximal convoluted tubule
Rationale
Approximately 65% of filtered sodium is reabsorbed in the proximal convoluted tubule.
Question 7 – Immunology
A patient with recurrent bacterial infections has absent mature B lymphocytes and markedly
decreased immunoglobulin levels.
Which condition is most likely?
A. Severe combined immunodeficiency
B. DiGeorge syndrome
C. X-linked agammaglobulinemia
D. Chronic granulomatous disease
E. Common variable immunodeficiency
, ✅ Answer: C. X-linked agammaglobulinemia
Rationale
X-linked agammaglobulinemia (Bruton disease) is caused by a mutation in Bruton's tyrosine kinase,
preventing B-cell maturation.
Question 8 – Osteopathic Principles
A patient develops low back pain after lifting a heavy object. Examination reveals hypertonic lumbar
paraspinal muscles without neurologic deficits.
Which osteopathic treatment is generally appropriate after serious pathology has been excluded?
A. Balanced ligamentous tension
B. Counterstrain
C. Muscle energy
D. High-velocity, low-amplitude (HVLA)
E. Any of the above, depending on the patient's presentation
✅ Answer: E. Any of the above, depending on the patient's presentation
Rationale
The appropriate OMT technique depends on the patient's diagnosis, tolerance, contraindications,
and treatment goals. There is no single technique that is universally preferred for all uncomplicated
low back pain.
Question 9 – Behavioral Science
A competent adult patient refuses a recommended blood transfusion because of religious beliefs.
The physician should:
A. Administer the transfusion anyway.
B. Obtain a court order immediately.
C. Respect the patient's informed refusal.
D. Ask the family to overrule the patient.
E. Transfer the patient without discussing risks.
✅ Answer: C. Respect the patient's informed refusal.
Rationale
Competent adults have the ethical and legal right to refuse medical treatment after receiving
appropriate information about the risks and benefits.
2025-2026
✅ Original COMSAE/COMLEX-style clinical vignette questions
✅ Multiple-choice answers (A–E)
✅ Correct answer
✅ Detailed rationale
✅ High-yield review pearls
Question 1 – Cardiovascular Physiology
A 65-year-old man presents with crushing substernal chest pain radiating to his left arm. An 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 wall myocardial infarction, most commonly
caused by occlusion of the right coronary artery (RCA).
High-Yield Pearl: Inferior MI → II, III, aVF → RCA.
Question 2 – Microbiology
A 22-year-old college student develops fever, headache, neck stiffness, and a petechial rash.
Cerebrospinal fluid culture grows gram-negative diplococci.
Which organism is most likely responsible?
A. Haemophilus influenzae
B. Neisseria meningitidis
C. Listeria monocytogenes
D. Streptococcus pneumoniae
E. Escherichia coli
✅ Answer: B. Neisseria meningitidis
Rationale
,The combination of meningitis and a petechial rash is classic for Neisseria meningitidis, a gram-
negative diplococcus.
High-Yield Pearl: Meningococcal disease can progress rapidly to septic shock and disseminated
intravascular coagulation.
Question 3 – Pharmacology
A patient with hypertension and diabetes has persistent microalbuminuria. Which medication
provides both blood pressure control and renal protection?
A. Hydrochlorothiazide
B. Metoprolol
C. Lisinopril
D. Amlodipine
E. Clonidine
✅ Answer: C. Lisinopril
Rationale
ACE inhibitors reduce intraglomerular pressure, decrease proteinuria, and help slow diabetic kidney
disease progression.
Question 4 – Pathology
A patient with long-standing gastroesophageal reflux develops intestinal metaplasia of the distal
esophagus.
This condition is called:
A. Achalasia
B. Barrett esophagus
C. Esophageal varices
D. Zenker diverticulum
E. Mallory-Weiss syndrome
✅ Answer: B. Barrett esophagus
Rationale
Chronic acid exposure causes replacement of normal squamous epithelium with intestinal-type
columnar epithelium, increasing the risk of esophageal adenocarcinoma.
Question 5 – Biochemistry
,A child presents with developmental delay and a musty body odor. Deficiency of which enzyme is
responsible?
A. Phenylalanine hydroxylase
B. Tyrosinase
C. Homogentisate oxidase
D. Branched-chain α-ketoacid dehydrogenase
E. Galactose-1-phosphate uridyltransferase
✅ Answer: A. Phenylalanine hydroxylase
Rationale
Phenylketonuria (PKU) results from deficiency of phenylalanine hydroxylase, causing accumulation of
phenylalanine.
Question 6 – Physiology
Which portion of the nephron reabsorbs the greatest percentage of filtered sodium?
A. Distal convoluted tubule
B. Collecting duct
C. Thick ascending limb
D. Proximal convoluted tubule
E. Thin descending limb
✅ Answer: D. Proximal convoluted tubule
Rationale
Approximately 65% of filtered sodium is reabsorbed in the proximal convoluted tubule.
Question 7 – Immunology
A patient with recurrent bacterial infections has absent mature B lymphocytes and markedly
decreased immunoglobulin levels.
Which condition is most likely?
A. Severe combined immunodeficiency
B. DiGeorge syndrome
C. X-linked agammaglobulinemia
D. Chronic granulomatous disease
E. Common variable immunodeficiency
, ✅ Answer: C. X-linked agammaglobulinemia
Rationale
X-linked agammaglobulinemia (Bruton disease) is caused by a mutation in Bruton's tyrosine kinase,
preventing B-cell maturation.
Question 8 – Osteopathic Principles
A patient develops low back pain after lifting a heavy object. Examination reveals hypertonic lumbar
paraspinal muscles without neurologic deficits.
Which osteopathic treatment is generally appropriate after serious pathology has been excluded?
A. Balanced ligamentous tension
B. Counterstrain
C. Muscle energy
D. High-velocity, low-amplitude (HVLA)
E. Any of the above, depending on the patient's presentation
✅ Answer: E. Any of the above, depending on the patient's presentation
Rationale
The appropriate OMT technique depends on the patient's diagnosis, tolerance, contraindications,
and treatment goals. There is no single technique that is universally preferred for all uncomplicated
low back pain.
Question 9 – Behavioral Science
A competent adult patient refuses a recommended blood transfusion because of religious beliefs.
The physician should:
A. Administer the transfusion anyway.
B. Obtain a court order immediately.
C. Respect the patient's informed refusal.
D. Ask the family to overrule the patient.
E. Transfer the patient without discussing risks.
✅ Answer: C. Respect the patient's informed refusal.
Rationale
Competent adults have the ethical and legal right to refuse medical treatment after receiving
appropriate information about the risks and benefits.
