Free Practice Questions for NBME CBSE
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Key Facts: NBME CBSE Exam
200
Official Items
NBME Timing Chart
5h 15m
Exam Length
NBME Timing Chart
12-16%
Reproductive & Endocrine
NBME Content Outline
11-15%
Respiratory & Renal
NBME Content Outline
$61
Local Fee Through Jun 2026
NBME Fee Page
$151
Prometric Fee Through Jun 2026
NBME Fee Page
CBSE is a 200-item, 5-hour-15-minute NBME comprehensive basic science exam used by medical schools and programs to assess progress and readiness for USMLE Step 1. There is no universal passing score; interpretation depends on the sponsoring institution. Preparation should emphasize integrated mechanisms across pathology, physiology, pharmacology, microbiology, immunology, biochemistry, genetics, anatomy, behavioral science, and biostatistics.
Sample NBME CBSE Practice Questions
Try these sample questions to review concepts for the NBME CBSE exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 121+ question experience with AI tutoring.
1A newborn has truncus arteriosus, hypocalcemic tetany, recurrent viral infections, and an absent thymic shadow. Failure of migration of which embryologic cell population best explains the cardiovascular abnormality?
2A fetus is noted on ultrasound to have persistent soft tissue webbing between the digits. Which cellular process normally removes this tissue during limb development?
3A 7-month-old infant has fasting hypoglycemia, lactic acidosis, hyperuricemia, and massive hepatomegaly. A liver biopsy shows excess glycogen with normal structure. Which enzyme is most likely deficient?
4A 3-year-old boy has developmental delay, self-injurious biting, orange crystals in his diaper, and choreoathetosis. Accumulation of which metabolite is most directly responsible for the crystal finding?
5A sailor develops swollen gums, perifollicular hemorrhages, poor wound healing, and corkscrew hairs after months at sea. Which posttranslational modification is impaired?
6A vegan patient develops macrocytic anemia, paresthesias, impaired vibration sense, and elevated methylmalonic acid. Which reaction is impaired by this vitamin deficiency?
7A woman with exercise intolerance, lactic acidosis, and ragged-red fibers has three children. All inherited the same mitochondrial DNA mutation, but their symptoms vary widely. Which concept best explains this variable severity?
8A man with early cataracts, frontal balding, distal muscle weakness, and difficulty releasing his grip has a daughter with more severe symptoms at a younger age. Which genetic mechanism explains this pattern?
9A population study finds that 1 in 10,000 newborns has an autosomal recessive enzyme deficiency. Assuming Hardy-Weinberg equilibrium, what is the approximate carrier frequency?
10A teenager with sickle cell disease develops severe pain after dehydration during basketball practice. Which molecular event initiates the red cell sickling in deoxygenated blood?
About the NBME CBSE Exam
The NBME Comprehensive Basic Science Examination is a secure, integrated achievement test covering material typically learned during basic science medical education, with somewhat greater emphasis on second-year content in traditional curricula. NBME states that CBSE reflects USMLE Step 1 content coverage and uses the same item formats. The official outline distributes foundational science across organ systems and includes medical knowledge, diagnosis, communication, and practice-based learning competencies.
Exam sponsor: NBME (National Board of Medical Examiners). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.
Questions
200 questions
Time Limit
5 hours, 15 minutes, including a 15-minute optional break
Passing Score
Institution-specific; no universal national passing score
Reported exam pass rate: Not published. NBME reports CBSE performance to schools and examinees, but schools set their own standards for passing or Step 1 clearance. Exam sponsor website
Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.
Our practice resources: topics covered
We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.
Human Development
Normal age-related findings, embryology, development, and care of the well patient.
Blood & Lymphoreticular/Immune Systems
Anemias, hemostasis, immune function, primary immunodeficiencies, hypersensitivity, and lymphoreticular pathology.
Behavioral Health & Nervous Systems/Special Senses
Neuroanatomy, neurologic disease mechanisms, psychiatry, behavioral science, eye, ear, and related pharmacology.
Musculoskeletal, Skin & Subcutaneous Tissue
Bone, muscle, joint, connective tissue, skin pathology, inflammation, and repair.
Cardiovascular System
Cardiac physiology, vascular biology, congenital lesions, valvular disease, shock, and cardiovascular pharmacology.
Respiratory & Renal/Urinary Systems
Pulmonary mechanics, oxygenation, renal transport, electrolyte disorders, acid-base physiology, and kidney pathology.
Gastrointestinal System
GI physiology, malabsorption, liver disease, pancreas, nutrition, and GI infectious or immune mechanisms.
Reproductive & Endocrine Systems
Hormone signaling, reproductive development, pregnancy, adrenal and thyroid physiology, diabetes, and endocrine tumors.
Multisystem Processes & Disorders
Inflammation, shock, infection, neoplasia, immune complex disease, granulomatous disease, and systemic pathology.
Biostatistics & Epidemiology/Population Health
Screening, diagnostic test performance, bias, study design, statistical interpretation, and population health.
Social Sciences: Communication and Interpersonal Skills
Ethics, communication, professionalism, health behavior, and patient-centered decision-making.
Preparing for the NBME CBSE Exam
What You Need to Know
- Passing score: Institution-specific; no universal national passing score
- Exam length: 200 questions
- Time limit: 5 hours, 15 minutes, including a 15-minute optional break
- Exam / certification fees: $61 local / $151 Prometric through June 30, 2026 Official sources
Using Our Practice Resources
- Work through all 121 available questions
- Review every answer and explanation
- Track weak areas and revisit them
- Use our AI tutor for tough concepts
NBME CBSE: Suggested Study Strategy
Frequently Asked Questions
What is the NBME CBSE?
The Comprehensive Basic Science Examination is an NBME comprehensive subject exam used by schools and programs to assess integrated basic science knowledge and readiness for USMLE Step 1.
How many questions are on CBSE?
The NBME timing chart lists Comprehensive Basic Science as a 200-item examination with a 5-hour, 15-minute exam length that includes a 15-minute optional break.
Does CBSE have a national passing score?
No universal passing score is published for CBSE. Schools and programs set their own score standards and use NBME reports to guide readiness decisions.
Is CBSE the same as USMLE Step 1?
No. CBSE is an NBME subject examination, but NBME states that it reflects Step 1 content coverage and uses the same item formats.
Can individuals buy the official CBSE as a practice test?
The official CBSE is ordered and administered by schools or sponsoring organizations in secure settings. Individuals typically use NBME self-assessments and other practice resources for independent preparation.