USMLE STEP 3 PRACTICE
EXAMINATION QUESTIONS WITH
CORRECT ANSWERS PLUS
RATIONALES 2026/2027 EDITION
WITH INSTANT PDF DOWNLOAD
Question 1
A 62-year-old man with hypertension, hyperlipidemia, and a 40-
pack-year smoking history presents with 45 minutes of substernal
chest pressure radiating to his left arm. ECG shows ST-segment
elevations in leads II, III, and aVF. He is given aspirin and a
sublingual nitrate, with minimal improvement. Blood pressure is
104/68 mm Hg. Which of the following is the most appropriate
next step?
A. Administer intravenous metoprolol
B. Administer fibrinolytic therapy immediately
C. Perform urgent coronary angiography with percutaneous
coronary intervention
D. Begin warfarin therapy
E. Obtain an exercise stress test
Correct Answer: C. Perform urgent coronary angiography with
percutaneous coronary intervention
Rationale: This patient has an acute ST-elevation myocardial
infarction (STEMI). When timely primary percutaneous coronary
intervention (PCI) is available, urgent coronary angiography with
,PCI is preferred because it rapidly restores coronary blood flow
and reduces mortality and complications. Fibrinolysis is generally
reserved for patients with STEMI when timely PCI cannot be
performed. Beta-blockers require caution in patients with
borderline blood pressure or other contraindications.
Question 2
A 28-year-old woman presents with fatigue, weight loss, heat
intolerance, tremulousness, and palpitations. Examination shows
diffuse thyroid enlargement and bilateral proptosis. Laboratory
studies reveal a suppressed TSH and elevated free T4. Which
medication is most appropriate for long-term control of her
hyperthyroidism?
A. Levothyroxine
B. Methimazole
C. Fludrocortisone
D. Desmopressin
E. Prednisone
Correct Answer: B. Methimazole
Rationale: Graves disease is characterized by diffuse thyroid
enlargement, ophthalmopathy, suppressed TSH, and elevated
thyroid hormone levels. Methimazole is generally preferred for
long-term treatment because it inhibits thyroid hormone
synthesis and has a lower risk of severe hepatotoxicity than
propylthiouracil. Propylthiouracil is preferred during the first
trimester of pregnancy and in thyroid storm because it also
inhibits peripheral conversion of T4 to T3.
,Question 3
A 71-year-old woman presents with sudden-onset right-sided
weakness and aphasia that began 90 minutes ago. CT of the head
shows no hemorrhage. Blood glucose is normal, and blood
pressure is 168/94 mm Hg. She takes no anticoagulants. Which of
the following is the most appropriate treatment?
A. Aspirin only
B. Intravenous alteplase
C. Intravenous heparin
D. Emergent carotid endarterectomy
E. Warfarin
Correct Answer: B. Intravenous alteplase
Rationale: This patient has an acute ischemic stroke presenting
within the therapeutic window for intravenous thrombolysis. Brain
imaging has excluded hemorrhage, and her blood pressure is
below the threshold that would preclude thrombolysis.
Intravenous alteplase can improve neurologic outcomes when
appropriately selected patients with acute ischemic stroke are
treated promptly.
Question 4
A 45-year-old man presents with severe epigastric pain radiating
to the back and persistent vomiting. Serum lipase is markedly
elevated. CT confirms acute pancreatitis. Which of the following
is the most appropriate initial management?
A. Immediate exploratory laparotomy
B. Aggressive intravenous fluid resuscitation and supportive care
C. Prophylactic broad-spectrum antibiotics for all patients
, D. Immediate total parenteral nutrition
E. Emergent cholecystectomy
Correct Answer: B. Aggressive intravenous fluid resuscitation
and supportive care
Rationale: Initial management of acute pancreatitis is primarily
supportive and includes adequate intravenous fluid resuscitation,
pain control, electrolyte management, and early enteral nutrition
when tolerated. Routine prophylactic antibiotics are not
recommended for uncomplicated acute pancreatitis.
Cholecystectomy is indicated during the same hospitalization for
mild gallstone pancreatitis once the patient has stabilized, but it is
not the initial treatment.
Question 5
A 35-year-old woman with type 1 diabetes mellitus presents with
nausea, vomiting, abdominal pain, and deep rapid breathing.
Laboratory studies show glucose 480 mg/dL, bicarbonate 9
mEq/L, and an elevated anion gap. Serum potassium is 5.1
mEq/L. Which treatment should be initiated first?
A. Intravenous insulin without fluids
B. Intravenous isotonic saline
C. Intravenous sodium bicarbonate
D. Intravenous potassium chloride
E. Subcutaneous long-acting insulin
Correct Answer: B. Intravenous isotonic saline
Rationale: This patient has diabetic ketoacidosis (DKA),
characterized by hyperglycemia, metabolic acidosis, and ketosis.
Initial treatment is isotonic intravenous fluid resuscitation to
EXAMINATION QUESTIONS WITH
CORRECT ANSWERS PLUS
RATIONALES 2026/2027 EDITION
WITH INSTANT PDF DOWNLOAD
Question 1
A 62-year-old man with hypertension, hyperlipidemia, and a 40-
pack-year smoking history presents with 45 minutes of substernal
chest pressure radiating to his left arm. ECG shows ST-segment
elevations in leads II, III, and aVF. He is given aspirin and a
sublingual nitrate, with minimal improvement. Blood pressure is
104/68 mm Hg. Which of the following is the most appropriate
next step?
A. Administer intravenous metoprolol
B. Administer fibrinolytic therapy immediately
C. Perform urgent coronary angiography with percutaneous
coronary intervention
D. Begin warfarin therapy
E. Obtain an exercise stress test
Correct Answer: C. Perform urgent coronary angiography with
percutaneous coronary intervention
Rationale: This patient has an acute ST-elevation myocardial
infarction (STEMI). When timely primary percutaneous coronary
intervention (PCI) is available, urgent coronary angiography with
,PCI is preferred because it rapidly restores coronary blood flow
and reduces mortality and complications. Fibrinolysis is generally
reserved for patients with STEMI when timely PCI cannot be
performed. Beta-blockers require caution in patients with
borderline blood pressure or other contraindications.
Question 2
A 28-year-old woman presents with fatigue, weight loss, heat
intolerance, tremulousness, and palpitations. Examination shows
diffuse thyroid enlargement and bilateral proptosis. Laboratory
studies reveal a suppressed TSH and elevated free T4. Which
medication is most appropriate for long-term control of her
hyperthyroidism?
A. Levothyroxine
B. Methimazole
C. Fludrocortisone
D. Desmopressin
E. Prednisone
Correct Answer: B. Methimazole
Rationale: Graves disease is characterized by diffuse thyroid
enlargement, ophthalmopathy, suppressed TSH, and elevated
thyroid hormone levels. Methimazole is generally preferred for
long-term treatment because it inhibits thyroid hormone
synthesis and has a lower risk of severe hepatotoxicity than
propylthiouracil. Propylthiouracil is preferred during the first
trimester of pregnancy and in thyroid storm because it also
inhibits peripheral conversion of T4 to T3.
,Question 3
A 71-year-old woman presents with sudden-onset right-sided
weakness and aphasia that began 90 minutes ago. CT of the head
shows no hemorrhage. Blood glucose is normal, and blood
pressure is 168/94 mm Hg. She takes no anticoagulants. Which of
the following is the most appropriate treatment?
A. Aspirin only
B. Intravenous alteplase
C. Intravenous heparin
D. Emergent carotid endarterectomy
E. Warfarin
Correct Answer: B. Intravenous alteplase
Rationale: This patient has an acute ischemic stroke presenting
within the therapeutic window for intravenous thrombolysis. Brain
imaging has excluded hemorrhage, and her blood pressure is
below the threshold that would preclude thrombolysis.
Intravenous alteplase can improve neurologic outcomes when
appropriately selected patients with acute ischemic stroke are
treated promptly.
Question 4
A 45-year-old man presents with severe epigastric pain radiating
to the back and persistent vomiting. Serum lipase is markedly
elevated. CT confirms acute pancreatitis. Which of the following
is the most appropriate initial management?
A. Immediate exploratory laparotomy
B. Aggressive intravenous fluid resuscitation and supportive care
C. Prophylactic broad-spectrum antibiotics for all patients
, D. Immediate total parenteral nutrition
E. Emergent cholecystectomy
Correct Answer: B. Aggressive intravenous fluid resuscitation
and supportive care
Rationale: Initial management of acute pancreatitis is primarily
supportive and includes adequate intravenous fluid resuscitation,
pain control, electrolyte management, and early enteral nutrition
when tolerated. Routine prophylactic antibiotics are not
recommended for uncomplicated acute pancreatitis.
Cholecystectomy is indicated during the same hospitalization for
mild gallstone pancreatitis once the patient has stabilized, but it is
not the initial treatment.
Question 5
A 35-year-old woman with type 1 diabetes mellitus presents with
nausea, vomiting, abdominal pain, and deep rapid breathing.
Laboratory studies show glucose 480 mg/dL, bicarbonate 9
mEq/L, and an elevated anion gap. Serum potassium is 5.1
mEq/L. Which treatment should be initiated first?
A. Intravenous insulin without fluids
B. Intravenous isotonic saline
C. Intravenous sodium bicarbonate
D. Intravenous potassium chloride
E. Subcutaneous long-acting insulin
Correct Answer: B. Intravenous isotonic saline
Rationale: This patient has diabetic ketoacidosis (DKA),
characterized by hyperglycemia, metabolic acidosis, and ketosis.
Initial treatment is isotonic intravenous fluid resuscitation to
