Step 1 One-day examination

Step 1 assesses whether you understand and can apply important concepts of the sciences basic to the practice of medicine, with special emphasis on principles and mechanisms underlying health, disease, and modes of therapy. Step 1 ensures mastery of not only the sciences that provide a foundation for the safe and competent practice of medicine in the present, but also the scientific principles required for maintenance of competence through lifelong learning. Step 1 is constructed according to an integrated content outline that organizes basic science material along two dimensions: system and process.

Step 1 is a one-day examination. It is divided into seven 60-minute blocks and administered in one 8-hour testing session. The number of questions per block on a given examination form may vary, but will not exceed 40. The total number of items on the overall examination form will not exceed 280.

Practice materials, which include Sample Test Items (PDF) and web-based Tutorial and Practice Test Items, as well as other informational materials, are available at the USMLE website. Examinees must also read the USMLE Bulletin of Information.

IMPORTANT:

  • The term item is used to describe a test question in any format.
  • You must run the web-based Tutorial and Practice Test Items to become familiar with the test software prior to your test date.
  • The tutorial provided at the beginning of the Step 1 Examination has fewer screens and less detailed information than the Step 1 web-based Tutorial and Practice Test Items on the USMLE website.
  • The web-based Tutorial and Practice Test Items on the USMLE website include items with associated audio findings. Become familiar with how these types of test items function before your test date.

Please visit the USMLE website often to view announcements, regarding changes in the test delivery software, and to access updated practice materials. You must obtain the most recent information before taking any USMLE examination.

All USMLE examinations are constructed from an integrated content outline, which 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. Content weighting for these topics is provided in Table 1. Sections focusing on individual organ systems are subdivided according to normal and abnormal processes, including principles of therapy. Content weighting for these topics is provided in Table 2. In most instances, knowledge of normal processes is evaluated in the context of a disease process or specific pathology. While not all topics listed in the content outline are included in every USMLE examination, overall content coverage is comparable among the various examination forms that will be taken by different examinees for each Step.

Table 1: Step 1 Test Specifications*

System Range %
General Principles ** 13-17
Blood & Lymphoreticular/Immune Systems 7-11
Behavioral Health & Nervous Systems/Special Senses 9-13
Musculoskeletal, Skin & Subcutaneous Tissue 6-10
Cardiovascular System 6-10
Respiratory & Renal/Urinary Systems 9-13
Gastrointestinal System 5-9
Reproductive & Endocrine Systems 9-13
Multisystem Processes & Disorders 7-11
Biostatistics & Epidemiology/Population Health 5-7
Social Sciences: Communication Skills/Ethics 3-5

* Percentages are subject to change at any time. See the USMLE website for the most up-to-date information.
** The General Principles category for the Step 1 examination 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.

Table 2: Step 1 Process Specifications

Process Range, %
Normal Processes† 10-15
Abnormal Processes 55-60
Principal of Therapeutics 15-20
Other‡ 10-15

† This category includes questions about normal structure and function that may appear in the context of an abnormal clinical presentation.
‡ Approximately 10% to 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.

Physician Tasks/Competencies

An additional organizing construct for Step 1 design is physician tasks and competencies. Each test item is constructed to assess one of the competencies listed in Table 3.

Table 3: Step 1 Physician Tasks/Competencies Specifications*

Competency Range, %
Medical Knowledge: Applying Foundational Science Concepts 52-62

Patient Care: Diagnosis

  • History/Physical Examination
  • Laboratory/Diagnostic Studies
  • Diagnosis
20-30
Patient Care: Management

  • Health Maintenance/Disease Prevention
  • Pharmacotherapy
7-12
Communication/Professionalism 2-5
Practice-based Learning & Improvement 5-7

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

Finally, each Step 1 examination covers content related to traditionally defined disciplines and interdisciplinary areas listed in Table 4.

Table 4: Step 1 Discipline Specifications*

System Range, %
Pathology 45-52
Physiology 26-34
Pharmacology 16-23
Biochemistry & Nutrition 14-24
Microbiology & Immunology
15-22
Gross Anatomy & Embryology 11-15
Histology & Cell Biology 9-13
Behavioral Sciences 8-13
Genetics 5-9

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

Step 1 consists of multiple-choice questions prepared by examination committees composed of faculty members, teachers, investigators, and clinicians with recognized prominence in their respective fields. Committee members are selected to provide broad representation from the academic, practice, and licensing communities across the United States and Canada.

The test is designed to measure basic science knowledge. Some questions test the examinee’s fund of information per se, but the majority of questions require the examinee to interpret graphic and tabular material, to identify gross and microscopic pathologic and normal specimens, and to solve problems through application of basic science principles.

The content description 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.

Broad-based learning that establishes a strong general understanding of concepts and principles in the basic sciences is the best preparation for the examination.

Strategies


  • Read each question carefully. It is important to understand what is being asked.
  • Try to generate an answer and then look for it in the option list.
  • Alternatively, read each option carefully, eliminating those that are clearly incorrect.
  • Of the remaining options, select the one that is most correct.
  • If unsure about an answer, it is better to guess since unanswered questions are automatically counted as wrong answers.

Single-Item Questions


A single patient-centered vignette is associated with one question followed by four or more response options. The response options are lettered (ie, A, B, C, D, E). A portion of the questions involves interpretation of graphic or pictorial materials. You are required to select the best answer to the question. Other options may be partially correct, but there is only ONE BEST answer. This is the traditional, most frequently used multiple-choice question format on the examination.

The questions are prepared by examination committees composed of faculty members, teachers, investigators, and clinicians with recognized prominence in their respective fields. Committee members are selected to provide broad representation from the academic, practice, and licensing communities across the United States and Canada.

Example Item

A 32-year-old woman with type 1 diabetes mellitus has had progressive renal failure over the past 2 years. She has not yet started dialysis. Examination shows no abnormalities. Her hemoglobin concentration is 9 g/dL, hematocrit is 28%, and mean corpuscular volume is 94 m3. A blood smear shows normochromic, normocytic cells. Which of the following is the most likely cause?

  • Acute blood loss
  • Chronic lymphocytic leukemia
  • Erythrocyte enzyme deficiency
  • Erythropoietin deficiency
  • Immunohemolysis
  • Microangiopathic hemolysis
  • Polycythemia vera
  • Sickle cell disease
  • Sideroblastic anemia
  • β-Thalassemia trait

(Answer: D)