COMLEX vs USMLE: should DO students take both?
DO students must pass COMLEX-USA, which tests osteopathic principles and practice alongside the same medical knowledge as the USMLE. Some also take the USMLE to apply to residency programs more familiar with it, at extra cost and study time. Support for treating the two as equivalent is growing, so whether you need both depends on the programs you’re targeting.
From NBOME’s percentile score page and Level 1 content outline, and an American Medical Association issue brief on equal consideration of the two exams. Checked October 12, 2026.
| COMLEX-USA | USMLE | |
|---|---|---|
| Who must take it | DO students (colleges require Levels 1 and 2-CE to graduate) | MD students; optional for DO students |
| Osteopathic content | Yes; at least 12% of Level 1 is osteopathic principles and practice | No |
| First exam scoring | Level 1: pass/fail | Step 1: pass/fail |
| Second exam scoring | Level 2-CE: three-digit score | Step 2 CK: three-digit score |
| Run by | NBOME | FSMB and NBME |
When taking both makes sense
- Check your target programs. Some residency programs are more familiar with USMLE scores; others accept COMLEX equally.
- Count the cost. The AMA notes that DO students taking both pay two sets of exam fees and spend more time preparing and testing.
- Use the percentile converter. The NBOME’s tool helps programs and applicants compare COMLEX Level 2-CE scores within the testing cohort.
Common questions
Can I use USMLE prep for COMLEX?
Much of it overlaps, since both test the same core medical knowledge. You’ll need extra osteopathic principles and practice review for COMLEX.
Official source & community discussion
NBOME: percentile score converter (official) →
See related questions on Quora →