USMLE Step 2 Clinical Knowledge
The United States Medical Licensing Examination (USMLE) Step 2 Clinical Knowledge (Step 2 CK) is a standardized, computer-based test designed to assess a medical student's or graduate's ability to apply medical knowledge, skills, and understanding of clinical science essential for the provision of patient care under supervision, with an emphasis on principles of clinical sciences and basic science concepts pertinent to medicine.[1] It forms a critical component of the three-step USMLE sequence required for medical licensure in the United States, typically taken after Step 1 and before or concurrently with residency training.[1] Administered as a one-day examination at Prometric test centers worldwide, Step 2 CK consists of up to 318 multiple-choice items divided into eight 60-minute blocks, conducted within a single 9-hour testing session that includes a minimum of 45 minutes of break time and an optional 15-minute tutorial.[2] Each block contains no more than 40 questions, focusing on single-best-answer formats, including sequential items, abstract-based questions, and multimedia (audio/video) that test clinical decision-making in patient scenarios.[3] The exam is offered year-round, with registration handled through the National Board of Medical Examiners (NBME) for U.S. and Canadian students or the Educational Commission for Foreign Medical Graduates (ECFMG) for international medical graduates.[1] Content coverage is organized around organ systems (such as cardiovascular system at 6–12% and social sciences including ethics and professionalism at 10–15%), physician tasks (such as diagnosis at 16–20% and mixed management at 12–16%), and major medical disciplines (with medicine comprising 55–65% of items).[3] The test integrates foundational sciences like biostatistics, ethics, and epidemiology, while prioritizing patient-centered skills such as health promotion, disease prevention, and pharmacotherapy (8–12% of items).[3] Eligibility requires passing USMLE Step 1 or meeting ECFMG criteria for international applicants, and the exam must be completed before advancing to Step 3.[1] Scores are reported on a three-digit scale, with a pass/fail outcome determined by a minimum passing standard of 218 (effective for exams taken on or after July 1, 2025), based on equating to ensure consistency across test forms.[4] Results, including performance profiles by content area, are typically available 3–4 weeks after testing via secure online portals, and passing Step 2 CK is essential for residency matching through the National Resident Matching Program (NRMP).[4] High performance on Step 2 CK correlates with success in postgraduate training and licensure; for U.S. MD seniors, mean scores for matched applicants typically range from 245 to 249 depending on specialty.[5]Overview
Purpose and Scope
The United States Medical Licensing Examination (USMLE) Step 2 Clinical Knowledge (CK) primarily assesses a medical student's or graduate's ability to apply medical knowledge, skills, concepts, and principles of clinical sciences that are essential for providing patient care under supervision. This evaluation emphasizes health promotion, disease prevention, and clinical reasoning to ensure examinees can integrate foundational biomedical knowledge with practical clinical scenarios. The exam tests the application of these elements in contexts that simulate real-world medical practice, focusing on safe and effective decision-making.[1][6] In scope, Step 2 CK covers the principles underlying patient management across various organ systems, bridging basic sciences with clinical practice to prepare candidates for the complexities of supervised care. It is typically taken after the completion of core clinical clerkships during the third year of medical school, allowing examinees to demonstrate readiness for advanced training. Unlike earlier steps that prioritize foundational recall, this exam stresses the synthesis of knowledge for diagnostic, therapeutic, and preventive interventions.[2][3] Step 2 CK has been part of the USMLE since its inception in 1992 as the clinical knowledge component of Step 2, with Step 2 Clinical Skills (CS) added in 2004 and discontinued in January 2021 due to evolving medical education needs and the COVID-19 pandemic. This structure underscores the exam's role in evaluating preparedness for unsupervised practice post-residency, while focusing on supervised care competencies during training. The discontinuation of Step 2 CS shifted greater emphasis to Step 2 CK as a key measure of clinical knowledge.[7][8] As of 2023-2024, approximately 44,000-45,000 examinees take Step 2 CK annually, including around 28,000 from US and Canadian medical schools and 16,000-17,000 from international programs, reflecting its central position in the licensure pathway for a diverse cohort of aspiring physicians.[9]Eligibility and Registration
Eligibility for the USMLE Step 2 Clinical Knowledge (CK) exam is restricted to medical students and graduates who meet specific educational criteria. Candidates must be officially enrolled in, or graduates of, a U.S. or Canadian medical school program leading to the MD degree accredited by the Liaison Committee on Medical Education (LCME), or a program leading to the DO degree accredited by the Commission on Osteopathic College Accreditation (COCA). International medical graduates (IMGs) are eligible if they are students or graduates of a medical school outside the U.S. and Canada that is listed in the World Directory of Medical Schools and meets the Educational Commission for Foreign Medical Graduates (ECFMG) eligibility criteria. Additionally, for Step 2 CK, the medical school dean (for U.S./Canadian candidates) or ECFMG must certify that the candidate has completed, or is near completion of, all core clinical clerkships in the basic medical sciences curriculum.[10][11][12] The registration process begins with submitting an application through the appropriate entity. U.S. and Canadian medical students and graduates apply via the National Board of Medical Examiners (NBME) website using the MyUSMLE portal, while IMGs apply through the ECFMG's MyIJE system after initiating an application for ECFMG Certification. Applications require a USMLE identification number, certification of eligibility by the medical school dean or ECFMG sponsor, and payment of the non-refundable application fee of $680 for U.S./Canadian applicants via NBME or $1,020 for IMGs via ECFMG, effective 2025. Once submitted, applications are typically processed within one to two weeks, after which eligible candidates receive a scheduling permit valid for a three-month eligibility period.[13][14][11][15][16] Scheduling for Step 2 CK occurs year-round at Prometric test centers worldwide, with candidates using their scheduling permit to select an exam date up to six months in advance via the Prometric website. Rescheduling is permitted but incurs fees if done within 45 days of the original appointment date, and the new date must fall within the assigned eligibility period; extensions to the eligibility period are available for a fee if needed. Candidates are limited to a maximum of four attempts per Step exam, with no more than three attempts allowed within any 12-month period; a fourth attempt requires at least 12 months since the first attempt and six months since the most recent attempt.[1][14][17][11][18] Special accommodations for examinees with documented disabilities are available under the Americans with Disabilities Act (ADA) and include provisions such as extended testing time, separate testing rooms, or assistive devices. Requests must be submitted to the NBME Disability Services using the official Request for Test Accommodations form, accompanied by a personal statement, clinical documentation from qualified professionals, and other objective evidence of the disability; medical schools may also provide a Certification of Test Accommodations form. Submissions should occur well in advance of the desired eligibility period, as processing typically takes up to 60 business days.[19][14][20]Exam Administration
Format and Structure
The USMLE Step 2 Clinical Knowledge (CK) examination is a computer-based, one-day test administered in a single 9-hour session. It consists of eight 60-minute blocks, each containing up to 40 questions, for a total of up to 318 items across the exam.[2][3] The testing session begins with an optional 15-minute tutorial to familiarize examinees with the computer interface and question formats; any time remaining from completing the tutorial early is added to the overall break time. Following the fourth block, examinees receive a designated 45-minute break, which can be divided and used at their discretion between blocks. Additional optional breaks are permitted between other blocks, drawing from the total allotted break time for transitions and rest, though starting a break deducts from this pool and cannot interrupt an active block.[21][2] All questions on the exam are in multiple-choice format, with examinees selecting the single best answer from provided options. The total item count includes both operational questions, which contribute to the score, and an undisclosed number of experimental or pretest items, which are not scored and are indistinguishable to test-takers. There is no penalty for guessing on any question, encouraging examinees to answer every item.[3][2] As of 2025, the block structure and overall timing remain unchanged from prior years, maintaining the exam's focus on efficient assessment of clinical knowledge under timed conditions.[3]Test Delivery and Policies
The USMLE Step 2 Clinical Knowledge (CK) exam is administered as a fully computerized test at Prometric test centers worldwide.[6] These centers number in the hundreds globally, with appointments scheduled on a first-come, first-served basis via the Prometric website after receiving a scheduling permit from the appropriate registration entity.[14] The exam interface is available exclusively in English, and an on-screen scientific calculator is provided for use, along with an erasable noteboard and marker for scratch work.[22] Test center policies strictly prohibit personal items in the secure testing area, including electronic devices, notes, and study materials, which must be stored in provided lockers.[23] Security measures include presentation of valid photo identification upon arrival, continuous audio and visual monitoring throughout the session, and supervision by test center staff.[23] Any misconduct, such as unauthorized assistance, disruptive behavior, or possession of prohibited items, may result in immediate dismissal, score invalidation, annotation on the score transcript, and potential bans from future USMLE administrations.[24] Examinees are required to report to the center at least 30 minutes early and must follow all staff instructions to avoid irregular behavior findings.[23] The USMLE program provides reasonable accommodations for examinees with documented disabilities in accordance with the Americans with Disabilities Act (ADA), including extended testing time, additional breaks, and allowances for medical devices or needs such as breastfeeding.[19] Requests are submitted via a dedicated form with supporting documentation to the NBME, typically reviewed within 60 business days; approvals may grant up to 100% additional time based on individual circumstances, though partial accommodations are common.[25] For medical conditions requiring extra breaks (e.g., diabetes management), a separate request form allows up to 15 minutes per block without counting against standard break time.[26] In cases of test center irregularities, such as closures or technical disruptions, examinees should notify staff immediately and follow up via email to [email protected] within 10 days.[27] The USMLE program may offer rescheduling without additional fees, score the exam as administered, void the results, or provide a free retest after investigation.[27] COVID-19-specific protocols, including masking or enhanced cleaning, were phased out by 2023, with current guidance advising rescheduling if the examinee is ill.[28] For international medical graduates (IMGs), Step 2 CK is available at Prometric centers in numerous countries, subject to ECFMG eligibility verification and an additional international test delivery surcharge.[29] IMGs apply through the ECFMG website, ensuring their medical school is listed in the World Directory of Medical Schools.[12]Content Outline
Organ Systems Coverage
The USMLE Step 2 Clinical Knowledge (CK) exam assesses a candidate's ability to apply medical knowledge, skills, and understanding of clinical science, with content organized primarily by organ systems and multisystem processes.[3] Questions emphasize the application of this knowledge to clinical scenarios, such as managing hypertension in the cardiovascular system or addressing sepsis in multisystem processes.[3] The proportional coverage across these categories is outlined in the official USMLE content specifications, providing approximate ranges that may vary by exam form to ensure balanced assessment.[3] These proportions reflect an integrated approach, where organ system topics are distributed across clinical disciplines rather than isolated by specialty.[3] The following table summarizes the coverage ranges for Step 2 CK:| Organ System or Process | Approximate Percentage |
|---|---|
| Human Development | 2–4% |
| Immune System | 3–5% |
| Blood & Lymphoreticular System | 3–6% |
| Behavioral Health | 5–10% |
| Nervous System & Special Senses | 5–10% |
| Musculoskeletal System/Skin & Subcutaneous Tissue | 6–12% |
| Cardiovascular System | 6–12% |
| Respiratory System | 5–10% |
| Gastrointestinal System | 5–10% |
| Renal & Urinary System & Reproductive Systems | 7–13% |
| Pregnancy, Childbirth & the Puerperium | 3–7% |
| Endocrine System | 3–7% |
| Multisystem Processes & Disorders | 4–8% |
| Biostatistics & Epidemiology/Population Health/Interpretation of Medical Literature | 3–5% |
| Social Sciences: Legal/Ethical Issues & Professionalism/Systems-based Practice & Patient Safety | 10–15% |
Physician Tasks and Competencies
The USMLE Step 2 Clinical Knowledge (CK) exam assesses a range of physician tasks and competencies essential for safe and effective patient care, emphasizing the application of clinical knowledge in real-world scenarios. These tasks are categorized into specific areas, each with proportional representation in the exam questions, as outlined in the official specifications. Foundational science concepts are integrated throughout rather than tested as a standalone category.[3] The following table summarizes the physician tasks/competencies and their approximate percentages on Step 2 CK:| Task/Competency | Percentage Range |
|---|---|
| Patient Care: Laboratory/Diagnostic Studies | 13-17% |
| Patient Care: Diagnosis | 16-20% |
| Patient Care: Prognosis/Outcome | 5-9% |
| Patient Care: Health Maintenance/Disease Prevention | 5-10% |
| Patient Care: Pharmacotherapy | 8-12% |
| Patient Care: Clinical Interventions | 6-10% |
| Patient Care: Mixed Management | 12-16% |
| Practice-based Learning & Improvement | 3-5% |
| Professionalism | 5-7% |
| Systems-based Practice & Patient Safety | 5-7% |
Discipline Proportions
The USMLE Step 2 Clinical Knowledge (CK) exam assesses knowledge across core medical disciplines, with questions distributed according to approximate proportions that reflect the breadth of clinical practice encountered in residency training.[3] These proportions emphasize foundational areas while allowing for integration across specialties, ensuring examinees demonstrate competency in managing common patient presentations.[3] The official content outline specifies the following ranges for discipline coverage, which may vary slightly between exam forms to maintain security and balance:[3]| Discipline | Proportion |
|---|---|
| Medicine | 55–65% |
| Surgery | 20–30% |
| Pediatrics | 17–27% |
| Obstetrics & Gynecology | 10–20% |
| Psychiatry | 10–15% |