COMLEX -USA LEVEL 1 EXAMINATION QUESTIONS
AND CORRECT ANSWER WITH DETAILED
EXPLANATION GRADED A+ STUDY GUIDE
OSTEOPAATHIC MEDICAL STUDENT
1. A 65-year-old man with COPD presents with hypoxia. Which acid-base disorder is most
likely?
A. Metabolic alkalosis
B. Respiratory acidosis
C. Metabolic acidosis
D. Respiratory alkalosis
Answer: B
COPD causes CO₂ retention leading to respiratory acidosis due to hypoventilation.
2. A child presents with edema, proteinuria, and lipiduria. Diagnosis?
A. Minimal change disease
B. FSGS
C. PSGN
D. IgA nephropathy
Answer: A
Minimal change disease is the most common cause of nephrotic syndrome in children
and shows effacement of podocyte foot processes.
3. Which organism causes peptic ulcers most commonly?
A. E. coli
B. H. pylori
C. S. aureus
D. C. difficile
Answer: B
Helicobacter pylori damages gastric mucosa via urease and inflammation leading to
ulcers.
4. Vitamin deficiency causing scurvy?
A. Vitamin A
B. Vitamin C
C. Vitamin D
, D. Vitamin K
Answer: B
Vitamin C deficiency impairs collagen hydroxylation causing bleeding gums and poor
wound healing.
5. Most common cause of community-acquired pneumonia?
A. Klebsiella
B. Streptococcus pneumoniae
C. Pseudomonas
D. Mycoplasma
Answer: B
Streptococcus pneumoniae is the most common cause of CAP in adults.
6. A patient has tremor, tachycardia, heat intolerance. Likely diagnosis?
A. Hypothyroidism
B. Graves disease
C. Addison disease
D. Cushing syndrome
Answer: B
Graves disease causes hyperthyroidism with TSH receptor stimulation.
7. Which electrolyte is most important in cardiac conduction?
A. Calcium
B. Potassium
C. Sodium
D. Chloride
Answer: B
Potassium determines resting membrane potential and cardiac excitability.
8. Which tumor is associated with Schistosoma haematobium?
A. Renal cell carcinoma
B. Bladder squamous cell carcinoma
C. Hepatocellular carcinoma
D. Testicular seminoma
Answer: B
Chronic infection causes squamous metaplasia leading to bladder cancer.
9. First-line treatment for anaphylaxis?
A. Diphenhydramine
B. Epinephrine
, C. Steroids
D. Albuterol
Answer: B
Epinephrine is life-saving via vasoconstriction and bronchodilation.
10. Which artery supplies the lateral brain surface?
A. ACA
B. MCA
C. PCA
D. Basilar artery
Answer: B
Middle cerebral artery supplies lateral cerebral cortex.
11. What is the mechanism of penicillin?
A. Protein synthesis inhibition
B. Cell wall synthesis inhibition
C. DNA gyrase inhibition
D. Folate inhibition
Answer: B
Penicillin inhibits transpeptidase in bacterial cell wall synthesis.
12. Most common cause of meningitis in neonates?
A. S. pneumoniae
B. N. meningitidis
C. Group B strep
D. Listeria monocytogenes
Answer: C
Group B strep is common in neonates.
13. Which disease has Reed-Sternberg cells?
A. NHL
B. Hodgkin lymphoma
C. ALL
D. AML
Answer: B
Reed-Sternberg cells are diagnostic for Hodgkin lymphoma.
14. What is the function of surfactant?
A. Increase surface tension
B. Decrease surface tension
AND CORRECT ANSWER WITH DETAILED
EXPLANATION GRADED A+ STUDY GUIDE
OSTEOPAATHIC MEDICAL STUDENT
1. A 65-year-old man with COPD presents with hypoxia. Which acid-base disorder is most
likely?
A. Metabolic alkalosis
B. Respiratory acidosis
C. Metabolic acidosis
D. Respiratory alkalosis
Answer: B
COPD causes CO₂ retention leading to respiratory acidosis due to hypoventilation.
2. A child presents with edema, proteinuria, and lipiduria. Diagnosis?
A. Minimal change disease
B. FSGS
C. PSGN
D. IgA nephropathy
Answer: A
Minimal change disease is the most common cause of nephrotic syndrome in children
and shows effacement of podocyte foot processes.
3. Which organism causes peptic ulcers most commonly?
A. E. coli
B. H. pylori
C. S. aureus
D. C. difficile
Answer: B
Helicobacter pylori damages gastric mucosa via urease and inflammation leading to
ulcers.
4. Vitamin deficiency causing scurvy?
A. Vitamin A
B. Vitamin C
C. Vitamin D
, D. Vitamin K
Answer: B
Vitamin C deficiency impairs collagen hydroxylation causing bleeding gums and poor
wound healing.
5. Most common cause of community-acquired pneumonia?
A. Klebsiella
B. Streptococcus pneumoniae
C. Pseudomonas
D. Mycoplasma
Answer: B
Streptococcus pneumoniae is the most common cause of CAP in adults.
6. A patient has tremor, tachycardia, heat intolerance. Likely diagnosis?
A. Hypothyroidism
B. Graves disease
C. Addison disease
D. Cushing syndrome
Answer: B
Graves disease causes hyperthyroidism with TSH receptor stimulation.
7. Which electrolyte is most important in cardiac conduction?
A. Calcium
B. Potassium
C. Sodium
D. Chloride
Answer: B
Potassium determines resting membrane potential and cardiac excitability.
8. Which tumor is associated with Schistosoma haematobium?
A. Renal cell carcinoma
B. Bladder squamous cell carcinoma
C. Hepatocellular carcinoma
D. Testicular seminoma
Answer: B
Chronic infection causes squamous metaplasia leading to bladder cancer.
9. First-line treatment for anaphylaxis?
A. Diphenhydramine
B. Epinephrine
, C. Steroids
D. Albuterol
Answer: B
Epinephrine is life-saving via vasoconstriction and bronchodilation.
10. Which artery supplies the lateral brain surface?
A. ACA
B. MCA
C. PCA
D. Basilar artery
Answer: B
Middle cerebral artery supplies lateral cerebral cortex.
11. What is the mechanism of penicillin?
A. Protein synthesis inhibition
B. Cell wall synthesis inhibition
C. DNA gyrase inhibition
D. Folate inhibition
Answer: B
Penicillin inhibits transpeptidase in bacterial cell wall synthesis.
12. Most common cause of meningitis in neonates?
A. S. pneumoniae
B. N. meningitidis
C. Group B strep
D. Listeria monocytogenes
Answer: C
Group B strep is common in neonates.
13. Which disease has Reed-Sternberg cells?
A. NHL
B. Hodgkin lymphoma
C. ALL
D. AML
Answer: B
Reed-Sternberg cells are diagnostic for Hodgkin lymphoma.
14. What is the function of surfactant?
A. Increase surface tension
B. Decrease surface tension
