USMLE Step 1 Practice Questions
Free USMLE Step 1 practice questions, grouped by the official USMLE Content Outline. Every question has a written explanation: why the answer is right, why each other option is wrong, and the high-yield facts to keep, with an official source for every fact.
Practice questions by system
Cardiovascular
Valvular heart disease
16 practice questions with written explanations
Murmurs, valve lesions and their causes.
Endocrine
Thyroid disorders
32 practice questions with written explanations
Graves disease, Hashimoto thyroiditis and thyroiditis.
No topics for this system yet.
More topics are on the way. See the full list on the Topics page.
How each practice set works
- The question, with time to think before you open the answer.
- The answer, starting from the key clue in the question.
- Why the other options are wrong, one by one.
- High-yield tips with the facts worth remembering.
- Sources for every fact, all official (NIH, CDC, FDA, guidelines).