COMLEX Level 1 overview

The COMLEX is created by the NBOME (The National Board of Osteopathic Medical Examiners) and consists of three parts. COMLEX Level 1 is taken after a student has completed two years of medical school at an Osteopathic institution and tests the basic science knowledge of the student on the fundamental mechanisms of pathologic illnesses as well as essential human processes. COMLEX Level 2 and COMLEX Level 3 deal with the clinical aspect of medicine.

The following disciplines are highly tested on the COMLEX Level 1:

  • Anatomy
  • Behavioral science
  • Biochemistry
  • Microbiology
  • Osteopathic principles
  • Pathology
  • Pharmacology
  • Physiology

COMLEX Level 1 question format

The COMLEX Level 1 is given in one day and is divided into two four-hour exam sessions. These two sessions are divided by a forty-minute break – the sessions also contain a ten minute break each.

The question format of the exam includes the “choose the best answer”, matching, as well as case clusters. These are clinical scenarios that often have two or even three questions following it relating to the situation that was described in the vignette.

For more information on the new computer test changes, visit the NBOME website.

COMLEX Level 1 score distribution

The mean 3-digit score on Level 1 is 500 – with a minimum passing score of 400. Whether you pass is determined by by performance on the overall exam, not by performance on individual subsections (COMLEX-CBT information). The minimum two digit passing score is 75.

Studying for the COMLEX Level 1

Like everything worthwhile, excelling on the Level 1 is difficult. Many students are encouraged to prepare for this examination from the first day they step into the classroom by paying attention in class, taking adequate notes, and making sure that a concept is grasped properly and not merely memorized. Among the most recommended sources for succeeding on the Level 1 exam are:

COMLEX I Preparation materials

The NBOME offers COMSAE – the Comprehensive Osteopathic Medical Self Assessment Examination. There are three phases that correspond to the three Levels of COMLEX cognitive testing. Also, there are multiple forms for each phase, so a candidate could take it more than once. COMSAE serves as a self-assessment tool with a format, structure and scoring very similar to that of the COMLEX.

The good news is that in addition to providing a good practice, COMSAE serves as a reasonably reliable estimate of how you will perform on the real exam. According to the NBOME, scores on COMSAE are highly correlated to scores on the real exams. On average COMLEX Level 1 scores were actually higher than that predicted by COMSAE Phase 1 scores.

In terms of question banks, most COMLEX prep materials are actually USMLE step 1 materials – primarily because there are few COMLEX-specific materials.

  • Kaplan USMLE step 1 question bank
  • Board Simulator Series for GI, Renal, Reproduction, Endocrinology published by Williams & Wilkins
  • High Yield Pharmacology, by Daryl Christ, published by Lippincot, Williams & Wilkins
  • Robbins: Review of Pathology, by Klatt & Kumar
  • The Princeton Review: Cracking the Boards, USMLE Step 1
  • Princeton Review books of questions
  • Pharmacology Recall
  • Jewitz’s Microbiology


1. National Board of Osteopathic Medical Examiners, Inc. (NBOME).

2. Osteopathic medical school and COMLEX forum

3. Student Survival Manual. Requirements for Comprehensive Medical Licensing Exams (COMLEX).

4. MomMD also has an excellent primer on NBOME, COMLEX materials and D.O. schools.

Topics #comlex #comlex level 1 #level 1 #nbome #osteopathic medicine #osteopathic principles #USMLE