USMLE® (United States Medical Licencing Exam)

he United States Medical Licensing Examination ® (USMLE®) is a three-step examination for medical licensure in the United States and is sponsored by the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners® (NBME®).
The USMLE assesses a physician’s ability to apply knowledge, concepts, and principles, and to demonstrate fundamental patient-centered skills, that are important in health and disease and that constitute the basis of safe and effective patient care. Each of the three Steps of the USMLE complements the others; no Step can stand alone in the assessment of readiness for medical licensure.

The USMLE Content Outline provides a common organization of content across all USMLE examinations. In addition, the USMLE Physician Tasks/Competencies, outline lists tasks and competencies assessed throughout the sequence of USMLE.

The USMLE Content Outline organizes content according to general principles and individual organ systems. Test questions are classified in one of 18 major areas, depending on whether they focus on concepts and principles that are important across organ systems or within individual organ systems.

Sections focusing on individual organ systems are subdivided according to normal and abnormal processes, including principles of therapy. Each Step 1 examination covers content related to the following traditionally defined disciplines:

  • anatomy
  • behavioral sciences
  • biochemistry
  • biostatistics and epidemiology
  • microbiology
  • pathology
  • pharmacology
  • physiology

The Step 1 examination also covers content related to the following interdisciplinary areas:

  • genetics
  • aging
  • immunology
  • nutrition
  • molecular and cell biology

While not all topics listed in the content outline are included in every USMLE examination, overall content coverage is comparable in the various examination forms that will be taken by different examinees for each Step.

Most organ systems are partitioned into Normal Processes and Abnormal Processes, and include subcategories of specific disease processes. In most instances, knowledge of normal processes is evaluated in the context of a disease process or specific pathology.

The content outline is not intended as a curriculum development or study guide. It provides a flexible structure for test construction that can readily accommodate new topics, emerging content domains, and shifts in emphasis. The categorizations and content coverage are subject to change. Broadly based learning that establishes a strong general understanding of concepts and principles in the basic sciences is the best preparation for the examination.

Step 1 classifies test items along two dimensions, system and process, as shown in Table 1 below.

Step 1 Test Specifications

Table 1: USMLE Step 1 Test Specifications*

General Principles of Foundational Science**
Immune System
Blood & Lymphoreticular System
Behavioral Health
Nervous System & Special Senses
Skin & Subcutaneous Tissue
Musculoskeletal System
Cardiovascular System
Respiratory System
Gastrointestinal System
Renal & Urinary System
Pregnancy, Childbirth, & the Puerperium
Female Reproductive & Breast
Male Reproductive
Endocrine System
Multisystem Processes & Disorders
Biostatistics & Epidemiology
Population Health
Social Sciences
Normal Processes†
Abnormal Processes
Principles of Therapeutics


In addition to being organized by organ systems, the Step 1 exam is organized by physician task and competency, as shown below. More information about the physician task and competency outline is available on the USMLE Web site ( Test items are constructed to assess one of the competencies listed below.

Table 2. USMLE Step 1 Specifications: Physician Task/Competencies*

Medical Knowledge/Scientific Concepts
55% – 65%
Patient Care: Diagnosis

  • History/Physical Examination
  • Laboratory/Diagnostic Studies
  • Diagnosis
  • Prognosis/Outcome
20% – 30%
Patient Care: Management***

  • Health Maintenance/Disease Prevention
  • Pharmacotherapy
Practice-based Learning and Improvement


* Percentages are subject to change at any time. See the USMLE Web site for the most up-to-date information.

** The general principles category includes test items concerning those normal and abnormal processes that are not limited to specific organ systems. Categories for individual organ systems include test items concerning those normal and abnormal processes that are system-specific.

*** The Step 1 examination includes management questions in only the categories listed in this table. It does not include questions related to clinical interventions, mixed management, or surveillance for disease recurrence. † This category includes questions about normal structure and function that may appear in the context of an abnormal clinical presentation.

‡ Approximately 10%-15% of questions are not classified in the normal processes, abnormal processes, or principles of therapeutics categories. These questions are likely to be classified in the general principles, biostatistics/evidence-based medicine, or social sciences categories in the USMLE Content Outline.