USMLE Practice Questions Answers Study Guide Physician Licensing Exam Clinical Medicine Review

Illinois Physician Licensing Examination
(USMLE) Practice Questions and Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A
1.A study finds an exposure increases disease risk by 2.0. This represents: A.
Relative risk
B. Absolute risk
C. Odds ratio
D. Incidence
Answer: A — Relative risk
Rationale: Relative risk compares disease incidence between exposed vs unexposed
groups.
2.High sensitivity means the test:
A. Rules in disease
B. Rules out disease
C. Has low false-negative
D. Has low false-positive
Answer: C — Low false-negative
Rationale: High sensitivity catches most true positives.
3.Incidence measures:
A. New cases/time
B. Total cases
C. Prevalence only
D. Mortality
Answer: A
4.P-value < .05 means:
A. 5% chance result is random
B. Significant difference
C. Clinical importance
D. No error
Answer: B
5.A Type I error means:
A. False negative
B. False positive
C. Random error
D. No error
Answer: B
6.Number needed to treat (NNT) is:
A. 1/ARR

, B. ARR × 100
C. RR − 1
D. OR/ARR
Answer: A
7.Confounding occurs when:
A. A third variable affects exposure & outcome
B. Sample is large
C. Randomization works
D. Blinding fails
Answer: A
8.Blinding reduces:
A. Confounding
B. Bias
C. Incidence
D. Prevalence
Answer: B
9.A case-control study calculates:
A. Relative risk
B. Odds ratio
C. Incidence
D. Prevalence
Answer: B
10.Randomization improves:
A. Internal validity
B. External validity
C. Prevalence
D. Sensitivity
Answer: A




11–20: Pharmacology
11.A patient on warfarin adds rifampin — INR will:
A. Increase
B. Decrease
C. Unchanged
D. Variable
Answer: B — Decrease
Rationale: Rifampin induces CYP → increased warfarin metabolism.
12.Which drug may cause torsades de pointes?
A. Metoprolol
B. Haloperidol
C. Morphine
D. Losartan
Answer: B