If you’re studying to become a medical doctor, you’ll need to take USMLE Step 1 before you start your clinical rotations and USMLE Step 2 CK before you receive your medical license. You’ve likely heard of these exams.
But if you’re planning to become a Doctor of Osteopathic Medicine (DO), there’s another exam series you need to know — the COMLEX. In this guide, we’ll walk you through each level of the COMLEX exam, how it compares to the USMLE, and what you should expect in 2025.
What Is the COMLEX-USA?
COMLEX-USA, administered by the National Board of Osteopathic Medical Examiners (NBOME), is a three-level examination series required for all DO students in the United States. COMLEX is designed to assess your readiness to care for patients using a holistic, osteopathic approach to medicine.
The exams include:
- Level 1 – Pre-clinical foundational knowledge
- Level 2-CE – Clinical knowledge after core rotations
- Level 3 – Independent medical decision-making as a resident
(Note: COMLEX Level 2-PE was permanently discontinued. More on that below.)
COMLEX Level 1
When You Take It
Typically taken at the end of your second year of medical school, following the completion of your pre-clinical courses.
What It Tests
Level 1 tests your ability to apply foundational medical sciences to clinical scenarios. The subjects include:
- Anatomy
- Biochemistry
- Microbiology
- Physiology
- Pathology
- Pharmacology
- Behavioral Science
- Osteopathic Principles and Practices (OPP)
This exam is designed to evaluate your readiness to enter clinical clerkships.
Structure
- 352 multiple-choice questions
- Administered in two 4-hour sessions in one day
- Computer-based
- Passing score: 400
Sample Question
A 22-year-old male marathon runner presents with right-sided rib pain during long runs. Physical exam shows exhalation dysfunction at ribs 4–5 on the right. Which muscle is most useful in correcting this dysfunction using a direct method?
A. Anterior scalene
B. Latissimus dorsi
C. Pectoralis minor
D. Quadratus lumborum
E. Serratus anterior
You can take a free practice exam on the NBOME website to get comfortable with the format.
Once you pass Level 1, you can begin your clinical clerkships.
COMLEX Level 2-CE (Cognitive Evaluation)
When You Take It
Usually taken during your fourth year, after completing your first year of core clinical rotations.
What It Tests
Level 2-CE simulates the thought process of a practicing physician. You’ll need to demonstrate clinical reasoning, diagnosis, and treatment planning skills across the following subjects:
- Emergency Medicine
- Family Medicine
- Internal Medicine
- OB/GYN
- Pediatrics
- Psychiatry
- Surgery
- Osteopathic Principles and Practices
Structure
- 352 multiple-choice questions
- Two 4-hour test blocks in one day
- Computer-based
- Passing score: 400
Sample Question
A 27-year-old male who uses IV drugs presents with fever, chills, joint pain, and chest pain. He has a systolic murmur and tender fingerpad nodules. What is the most likely causative organism?
A. Candida albicans
B. Enterococcus faecalis
C. Pseudomonas aeruginosa
D. Staphylococcus aureus
E. Streptococcus viridans
Passing Level 2-CE shows you’re ready to work with patients in a supervised clinical setting.
COMLEX Level 2-PE (Now Discontinued)
What Was It?
Previously, COMLEX Level 2-PE was a hands-on exam using standardized patients. It tested clinical and communication skills — including history taking, physical exams, documentation, and professionalism.
What Changed?
In June 2022, NBOME permanently discontinued COMLEX Level 2-PE due to concerns about fairness, cost, and accessibility, all magnified during the pandemic. The osteopathic community supported the move, and the change is now permanent.
What’s Replacing It?
In 2025, students must demonstrate clinical skills through in-school assessments, including:
- Observed standardized patient encounters
- Documentation and SOAP note evaluations
- Direct faculty evaluations
- Communication and professionalism assessments
Your medical school’s dean must formally attest that you’ve met all required competencies.
This new approach removes the travel burden and creates more equitable, school-based assessments — but the expectations remain high.
COMLEX Level 3
When You Take It
Usually, during your first or second year of residency, depending on your program.
What It Tests
Level 3 evaluates whether you’re ready to practice medicine independently. The exam focuses on:
- Clinical judgment
- Multisystem care
- Emergency response
- Chronic and acute management
- Osteopathic principles in practice
Disciplines Covered
- Family Medicine
- Internal Medicine
- Emergency Medicine
- OB/GYN
- Pediatrics
- Psychiatry
- Surgery
- OPP
Structure
- Two-day computer-based exam
- Day 1: General clinical knowledge
- Day 2: Includes 26 Clinical Decision-Making (CDM) cases
- Total: 420 multiple-choice questions + CDM scenarios
- Passing score: 350
Sample CDM Question:
A 66-year-old man with a previously stable abdominal aortic aneurysm now shows expansion to 5.6 cm on ultrasound. He is asymptomatic. What is the most appropriate next step?
A. Annual surveillance
B. Surgical repair
C. Beta-blocker therapy
D. Lifestyle modification
E. Repeat ultrasound in 6 months
Correct answer: B. Surgical repair
Practice resources, tutorials, and scoring information are available at the NBOME Level 3 Portal.
COMLEX vs. USMLE in 2025: Should You Take Both?
All DO students must take COMLEX. But should you take the USMLE too?
The answer depends on your goals.
You might take both if:
- You’re applying to competitive MD residency programs
- Your desired specialty (like dermatology or radiology) is highly selective
- The programs you’re targeting don’t fully understand COMLEX scores
Many ACGME-accredited residencies now accept COMLEX only, but taking USMLE Step 1 and Step 2 CK can increase your visibility and help you compete directly with MD applicants.
Still unsure? You can talk it through with your school’s advisor or schedule a free call with our consulting team.
How International Medical Aid Supports Osteopathic Students
At International Medical Aid (IMA), we’ve supported thousands of aspiring healthcare professionals — including DO students — with:
- Medical school admissions consulting
- Healthcare internships abroad
- Application support for both COMLEX and USMLE strategies
- Personal statement coaching, interview prep, and career mapping
We also offer global health experiences that enhance clinical exposure and give you a strong edge when applying for residencies.
Final Thoughts
The COMLEX exams are a required and meaningful part of your journey to becoming a licensed osteopathic physician. With COMLEX Level 2-PE retired, more emphasis now falls on in-school assessments and structured clinical experiences.
The first step is to know the structure, timeline, and expectations of each exam. Using official NBOME practice resources, developing a timeline with your school, and exploring options like IMA’s admissions consulting can help you move forward with clarity and confidence.
If you’re preparing for your COMLEX exams or weighing the value of taking the USMLE too, reach out. We’re here to support you.
