DO Study Guide 2026
Everything you need to pass the DO exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📚 DO Topics to Study (21)
✍️ Sample DO Questions & Answers
1. A.T. Still's famous statement that 'the role of the artery is supreme' emphasized the importance of which body system?
Still believed that unobstructed arterial blood flow was essential to health and that restoring circulation was central to healing.
2. A patient on carbamazepine for epilepsy presents with hyponatremia. What is the most likely mechanism?
Carbamazepine stimulates ADH release and potentiates its action on V2 receptors in renal collecting ducts, causing SIADH and hyponatremia.
3. Approximately how many DOs are currently practicing in the United States?
Approximately 180,000 DOs practice in the United States, representing about 25% of the total US physician workforce.
4. Which beta-blocker is most cardioselective and preferred when a beta-blocker is necessary in a patient with mild COPD?
Metoprolol selectively blocks beta-1 receptors with minimal beta-2 activity, reducing the risk of bronchospasm compared to non-selective agents.
5. A patient stabilized on warfarin is started on rifampin for latent TB. What is the expected effect on INR?
Rifampin is a potent CYP450 inducer that accelerates warfarin metabolism, significantly reducing INR and increasing clot risk.
6. Which subject area carries the greatest content weight on COMLEX Level 2-CE?
Internal medicine has the highest content weight on COMLEX Level 2-CE due to its broad clinical scope during rotations.