NBME 4 | USMLE Step 3 Practice Exam — 200 Questions with Verified Answers & Rationales
(2026 Q&A)
This comprehensive practice test bank simulates the style and difficulty of the USMLE Step 3
examination, covering all core domains including internal medicine, surgery, pediatrics,
obstetrics/gynecology, psychiatry, and preventive medicine.
Table of Contents
| Topic | Questions |
|-------|-----------|
| Topic 1: Cardiology & Vascular Medicine | 1–20 |
| Topic 2: Pulmonology & Critical Care | 21–35 |
| Topic 3: Gastroenterology & Hepatology | 36–50 |
| Topic 4: Endocrinology & Metabolism | 51–60 |
| Topic 5: Nephrology & Urology | 61–75 |
| Topic 6: Infectious Disease | 76–90 |
| Topic 7: Hematology & Oncology | 91–105 |
| Topic 8: Neurology | 106–120 |
| Topic 9: Psychiatry & Behavioral Health | 121–135 |
| Topic 10: Obstetrics & Gynecology | 136–150 |
| Topic 11: Pediatrics | 151–165 |
| Topic 12: Surgery & Trauma | 166–180 |
| Topic 13: Preventive Medicine & Biostatistics | 181–190 |
| Topic 14: Ethics, Professionalism & Patient Safety | 191–200 |
,Topic 1: Cardiology & Vascular Medicine (Questions 1–20)
1. A 65-year-old man with a history of hypertension and type 2 diabetes presents to the
emergency department with acute onset of substernal chest pressure radiating to his left arm,
accompanied by diaphoresis and nausea. ECG shows 2-mm ST-segment elevation in leads V1–
V4. Which of the following is the most appropriate immediate management?
A) Administer sublingual nitroglycerin and observe
B) Immediate percutaneous coronary intervention (PCI)
C) Administer thrombolytic therapy and transfer to ICU
D) Obtain a chest radiograph and cardiac enzymes
Answer: B
Rationale: This patient presents with an acute ST-segment elevation myocardial infarction
(STEMI) based on symptoms and ECG findings. Immediate PCI is the treatment of choice if it can
be performed within 90 minutes of first medical contact. Thrombolytic therapy is an alternative
if PCI is not available within that timeframe. Nitroglycerin alone is insufficient for acute STEMI
management.
---
2. A 72-year-old woman with a history of heart failure with preserved ejection fraction (HFpEF)
presents with progressive dyspnea on exertion and peripheral edema. Her blood pressure is
145/88 mmHg, heart rate is 78/min, and oxygen saturation is 94% on room air. Which of the
following is the most appropriate initial pharmacological therapy?
A) Digoxin
,B) Spironolactone
C) A beta-blocker
D) A loop diuretic
Answer: D
Rationale: In patients with HFpEF presenting with volume overload (dyspnea and edema), loop
diuretics are the mainstay of initial therapy to relieve congestive symptoms. While beta-blockers
and spironolactone may have roles in chronic management, diuresis is the priority for acute
symptom relief.
---
3. A 58-year-old man with a 30-pack-year smoking history presents with a 2-month history of
progressive shortness of breath and a nonproductive cough. Physical examination reveals
diminished breath sounds at the left lung base. Chest CT shows a 4-cm left lower lobe mass with
mediastinal lymphadenopathy. Which of the following is the most appropriate next step in
management?
A) CT-guided biopsy of the mass
B) Mediastinoscopy with lymph node biopsy
C) Positron emission tomography (PET) scan
D) Endobronchial ultrasound (EBUS)-guided biopsy
Answer: D
Rationale: In a patient with suspected lung cancer and mediastinal lymphadenopathy, EBUS-
guided biopsy allows sampling of both the primary tumor and mediastinal lymph nodes in a
, single procedure. This provides staging information and tissue diagnosis with lower morbidity
than mediastinoscopy.
---
4. A 45-year-old woman with a history of mitral valve prolapse presents with palpitations. ECG
shows an irregularly irregular rhythm with no discernible P waves. Which of the following is the
most appropriate next step in management?
A) Amiodarone loading
B) Direct current cardioversion
C) Rate control with a beta-blocker and anticoagulation
D) Referral for electrophysiology study
Answer: C
Rationale: The ECG findings are consistent with atrial fibrillation. For hemodynamically stable
patients, the initial approach involves rate control (beta-blocker or calcium channel blocker) and
assessment for anticoagulation based on CHA₂DS₂-VASc score. Rhythm control may be
considered later but is not the first step.
---
5. A 68-year-old man with a history of hypertension and hyperlipidemia presents with sudden
onset of severe, tearing chest pain radiating to his back. Blood pressure is 180/110 mmHg in the
right arm and 130/80 mmHg in the left arm. Which of the following is the most likely diagnosis?
A) Acute myocardial infarction
(2026 Q&A)
This comprehensive practice test bank simulates the style and difficulty of the USMLE Step 3
examination, covering all core domains including internal medicine, surgery, pediatrics,
obstetrics/gynecology, psychiatry, and preventive medicine.
Table of Contents
| Topic | Questions |
|-------|-----------|
| Topic 1: Cardiology & Vascular Medicine | 1–20 |
| Topic 2: Pulmonology & Critical Care | 21–35 |
| Topic 3: Gastroenterology & Hepatology | 36–50 |
| Topic 4: Endocrinology & Metabolism | 51–60 |
| Topic 5: Nephrology & Urology | 61–75 |
| Topic 6: Infectious Disease | 76–90 |
| Topic 7: Hematology & Oncology | 91–105 |
| Topic 8: Neurology | 106–120 |
| Topic 9: Psychiatry & Behavioral Health | 121–135 |
| Topic 10: Obstetrics & Gynecology | 136–150 |
| Topic 11: Pediatrics | 151–165 |
| Topic 12: Surgery & Trauma | 166–180 |
| Topic 13: Preventive Medicine & Biostatistics | 181–190 |
| Topic 14: Ethics, Professionalism & Patient Safety | 191–200 |
,Topic 1: Cardiology & Vascular Medicine (Questions 1–20)
1. A 65-year-old man with a history of hypertension and type 2 diabetes presents to the
emergency department with acute onset of substernal chest pressure radiating to his left arm,
accompanied by diaphoresis and nausea. ECG shows 2-mm ST-segment elevation in leads V1–
V4. Which of the following is the most appropriate immediate management?
A) Administer sublingual nitroglycerin and observe
B) Immediate percutaneous coronary intervention (PCI)
C) Administer thrombolytic therapy and transfer to ICU
D) Obtain a chest radiograph and cardiac enzymes
Answer: B
Rationale: This patient presents with an acute ST-segment elevation myocardial infarction
(STEMI) based on symptoms and ECG findings. Immediate PCI is the treatment of choice if it can
be performed within 90 minutes of first medical contact. Thrombolytic therapy is an alternative
if PCI is not available within that timeframe. Nitroglycerin alone is insufficient for acute STEMI
management.
---
2. A 72-year-old woman with a history of heart failure with preserved ejection fraction (HFpEF)
presents with progressive dyspnea on exertion and peripheral edema. Her blood pressure is
145/88 mmHg, heart rate is 78/min, and oxygen saturation is 94% on room air. Which of the
following is the most appropriate initial pharmacological therapy?
A) Digoxin
,B) Spironolactone
C) A beta-blocker
D) A loop diuretic
Answer: D
Rationale: In patients with HFpEF presenting with volume overload (dyspnea and edema), loop
diuretics are the mainstay of initial therapy to relieve congestive symptoms. While beta-blockers
and spironolactone may have roles in chronic management, diuresis is the priority for acute
symptom relief.
---
3. A 58-year-old man with a 30-pack-year smoking history presents with a 2-month history of
progressive shortness of breath and a nonproductive cough. Physical examination reveals
diminished breath sounds at the left lung base. Chest CT shows a 4-cm left lower lobe mass with
mediastinal lymphadenopathy. Which of the following is the most appropriate next step in
management?
A) CT-guided biopsy of the mass
B) Mediastinoscopy with lymph node biopsy
C) Positron emission tomography (PET) scan
D) Endobronchial ultrasound (EBUS)-guided biopsy
Answer: D
Rationale: In a patient with suspected lung cancer and mediastinal lymphadenopathy, EBUS-
guided biopsy allows sampling of both the primary tumor and mediastinal lymph nodes in a
, single procedure. This provides staging information and tissue diagnosis with lower morbidity
than mediastinoscopy.
---
4. A 45-year-old woman with a history of mitral valve prolapse presents with palpitations. ECG
shows an irregularly irregular rhythm with no discernible P waves. Which of the following is the
most appropriate next step in management?
A) Amiodarone loading
B) Direct current cardioversion
C) Rate control with a beta-blocker and anticoagulation
D) Referral for electrophysiology study
Answer: C
Rationale: The ECG findings are consistent with atrial fibrillation. For hemodynamically stable
patients, the initial approach involves rate control (beta-blocker or calcium channel blocker) and
assessment for anticoagulation based on CHA₂DS₂-VASc score. Rhythm control may be
considered later but is not the first step.
---
5. A 68-year-old man with a history of hypertension and hyperlipidemia presents with sudden
onset of severe, tearing chest pain radiating to his back. Blood pressure is 180/110 mmHg in the
right arm and 130/80 mmHg in the left arm. Which of the following is the most likely diagnosis?
A) Acute myocardial infarction
