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The USMLE Step 1 Topics You MUST Know for USMLE Step 2 CK
(System-by-System Guide)
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Updated June 2026
Preparing for USMLE Step 2 CK often raises the same question for almost every student:
“How much Step 1 do I actually need to review for Step 2 CK?”
The honest answer: less than you think, but more than zero.
Step 2 CK is a clinical exam, but a surprising number of questions still hinge on basic science: hormone feedback loops, nerve injury patterns, coagulation mechanisms, and ECG physiology. You need to know which mechanisms still show up and which ones you can safely leave behind.
That’s exactly what this guide gives you.
For every major system, we’ve pulled out only the Step 1 concepts that consistently appear on Step 2 CK and NBME-style questions. Use it system by system as you work through your Qbank refresh the relevant basics, then get into the questions. No wasted time, no unnecessary review.
Let’s get into it.
The goal is simple:
Keep the Step 1 content that matters, cut the rest, and save yourself dozens of hours of unnecessary review.
If you’re just starting your Step 2 CK prep, our Step 2 CK Bootcamp can help you set the right mindset early and understand the most high-yield concepts to focus on before diving into Qbanks.
If you need a personalized strategy or one-on-one expert guidance to push past your plateau, we’ve got you covered. Explore Our Expert USMLE Tutoring to get paired with a top-scoring physician and achieve your target score efficiently.
Stop wasting valuable study time trying to memorize low-yield details. Our Free High-Yield USMLE Notes 📚 for Step 1 and Step 2 CK are built for efficient learning, ensuring you master the core concepts necessary to ace both exams, even on a tight schedule.
Table of Contents
⭐ How to Use This Guide
This guide is not a full Step 1 review; it is a targeted checklist of the exact basic-science topics we recommend revisiting before doing Step 2 CK questions.
Here’s the most effective way to use it:
- Choose the system you’re about to study
Cardio, Neuro, GI, Endocrine, etc. - Read the bullet points for that system here
This tells you exactly which Step 1 core basic principles still show up on Step 2 CK. - Go to your Step 1 resources and review those topics
- Now start your Step 2 CK questions for that system
You’ll notice the vignettes make more sense because your mechanisms are already refreshed. - Repeat for every new system
This makes your prep more efficient, focused, and high-yield.
Now, let’s go through each system and highlight the Step 1 topics worth revisiting before starting your next Qbank block.
If you want a faster way to review the Step 1 concepts listed in this guide, you can use our Step 1 High-Yield Files, which summarize the key mechanisms in a focused, exam-oriented format.
✅ Get Full Access to All High-Yield NOTES – For FREE!
To access all the PDFs of the Step 1 High-Yield topics, sign up below and we’ll send them to your inbox, completely free.
♥️Cardiovascular
The cardiovascular system is one of the most frequently tested areas on USMLE Step 2 CK, and many questions still rely on core Step 1 physiology and pathophysiology. Reviewing these basic mechanisms makes it easier to interpret clinical vignettes on Step 2 CK.
- Physiology basics: heart sounds and murmurs with key bedside maneuvers; ANP/BNP physiology; and hemodynamic changes in shock (CO, preload, afterload patterns).
- Congenital & pediatric heart disease: cyanotic vs acyanotic lesions, timing of cyanosis, pathophysiology of coarctation of the aorta, and persistent pulmonary hypertension of the newborn.
- Vascular pathophysiology of primary vs secondary hypertension and major vascular disorders including aneurysm, aortic dissection, cholesterol emboli, and subclavian steal syndrome.
- Ischemic disease: core MI pathophysiology, biomarker interpretation, and high-yield ECG localization patterns.
- Basic mechanisms behind fundamental rhythm disturbances, including AV blocks, WPW, and narrow and wide-complex rhythms.
- Inflammatory & pericardial disease: pathophysiology of tamponade, acute vs chronic pericarditis, myocarditis, infective endocarditis, and rheumatic fever.
- Pharmacology (HY): mechanisms and major adverse effects of the key antiarrhythmics used on Step 2 CK: β-blockers, amiodarone, calcium-channel blockers, procainamide, and adenosine.
🧁Endocrine
Endocrine disorders on USMLE Step 2 CK frequently rely on core Step 1 hormone physiology and feedback regulation. Understanding these basic mechanisms makes it much easier to recognize classic presentations in NBME-style questions.
- Embryology & anatomy: thyroglossal duct cyst (midline mass differential) and basic thyroid/parathyroid anatomical relations relevant to endocrine disorders.
- Core hormone physiology: hypothalamic–pituitary axis regulation; insulin and glucagon in glucose homeostasis; cortisol and the HPA axis; and high-yield congenital adrenal hyperplasia (CAH) enzyme-deficiency patterns.
- Thyroid & parathyroid regulation: essential thyroid/parathyroid hormone functions and high-yield Ca/PTH trends in hypo- and hyperparathyroid states.
- Diagnostic endocrine pearls: characteristic hormonal patterns distinguishing hypothalamic, pituitary, and primary gland dysfunction; and basic pathophysiologic differences between DKA and HHS.
- Pharmacology (HY): mechanisms of action and key adverse effects of insulin types, metformin, sulfonylureas, thionamides, and fludrocortisone.
🍴Gastrointestinal System
GI disorders on USMLE Step 2 CK often depend on understanding core Step 1 embryology, anatomy, and pathophysiology. Many high-yield pediatric and adult GI questions require recognizing classic congenital patterns, malabsorption mechanisms, and key hepatic or biliary fundamentals that appear repeatedly in NBME-style exams.
- Congenital & structural basics: gastroschisis vs omphalocele, TEF, pyloric stenosis, duodenal atresia, and core inguinal hernia pathophysiology.
- Upper GI pathophysiology of achalasia, Barrett’s esophagus, autoimmune vs H. pylori gastritis, and gastric vs peptic ulcer fundamentals.
- Malabsorption & IBD: celiac disease (location + biopsy findings) with vitamin deficiencies, and key pathologic differences between Crohn disease and ulcerative colitis.
- Understand basic mechanisms of Zenker diverticulum, Meckel diverticulum, Hirschsprung disease, intussusception, and volvulus.
- Hepatic basics: pathophysiology of alpha-1 antitrypsin deficiency, hereditary hyperbilirubinemias, cholesterol and pigment gallstone formation, and the role of the APC mutation in FAP.
- Pharmacology (HY): mechanisms of PPIs, misoprostol, octreotide, lactulose, and ursodeoxycholic acid.
🩸Hematology & Oncology
Hematology and oncology questions on USMLE Step 2 CK rely heavily on core Step 1 physiology and cellular mechanisms. Recognizing classic anemia patterns, hemolysis pathways, coagulation defects, and oncologic associations is essential for interpreting NBME-style vignettes.
- Anemias & hemolysis: core pathophysiology of folate/B12 deficiency, anemia of chronic disease, and major hemolytic processes including hereditary spherocytosis, G6PD deficiency, autoimmune hemolysis, micro/macroangiopathic hemolysis, and sickle cell disease/trait.
- Neonatal hemolysis pathophysiology: Rh disease and ABO incompatibility.
- Coagulation disorders: pathophysiology of hemophilia A/B (factor deficiencies), mechanism of HIT and protein C depletion leading to warfarin-induced skin necrosis.
- Antithrombotic pharmacology: aspirin (COX inhibition), basic mechanism of factor Xa inhibitors, and thrombolytics with their core indications and contraindications.
- Oncologic associations & drugs: EBV and HTLV lymphoma associations, and key adverse effects of methotrexate.
💪Musculoskeletal & Rheumatology
- MSK and rheumatology topics on USMLE Step 2 CK often depend on basic Step 1 anatomy and immunology. Knowing these foundations helps you recognize nerve injuries, pediatric ortho conditions, and key autoimmune patterns on Step 2 CK.
- Peripheral nerve injuries: key deficits in axillary, median, ulnar, and radial nerve injuries; brachial plexus injury patterns; femoral, sciatic, superior gluteal, tibial, and common peroneal nerve involvement; median nerve compression in carpal tunnel.
- Ortho structural basics: scaphoid fracture significance; vertebral root levels causing radiculopathies; and avascular necrosis of the femoral head (pathophysiology and risk factors).
- Pediatric MSK pathophysiology of radial head subluxation, Osgood-Schlatter disease, SCFE, and developmental dysplasia of the hip.
- Bone & soft tissue tumors: typical locations of osteosarcoma, osteochondroma, and giant cell tumor.
- Rheumatologic basics: pathogenesis of osteoarthritis vs rheumatoid arthritis; key autoantibodies in lupus, antiphospholipid syndrome, and vasculitides; and the mechanisms of myasthenia gravis and Lambert-Eaton syndrome.
- Pharmacology (HY): acetaminophen overdose basics, aspirin/NSAID adverse effects.
🧠Neurology
Neurology on USMLE Step 2 CK relies heavily on core Step 1 neuroanatomy and lesion localization. Knowing these basic mechanisms makes it much easier to identify stroke patterns, neurologic deficits, and classic NBME neuro presentations.
- Congenital & structural pathophysiology of neural tube defects (anencephaly, spina bifida subtypes), Chiari I/II malformations, and syringomyelia.
- Core neuroanatomy in practice: UMN vs LMN lesions (including facial nerve patterns), tongue innervation (motor and sensory), and anatomical location of high-yield spinal cord lesion patterns (ALS, polio, SMA, tabes dorsalis, subacute combined degeneration).
- Cerebrovascular basics: ischemic vs hemorrhagic stroke foundations; anterior vs posterior circulation findings; types of intracranial hemorrhage; and common aneurysm anatomical locations.
- Neuromuscular & movement: Huntington disease inheritance clues and the pathophysiology of Guillain-Barré syndrome.
- Brain tumors key recognition patterns; glioblastoma (butterfly lesion), vestibular schwannoma (CN VIII), pituitary adenoma (endocrine effects), and craniopharyngioma (calcifications).
- Neuro-ophthalmology: basic mechanisms of retinal detachment, papilledema, and glaucoma; leukocoria in retinoblastoma; CN III motor vs parasympathetic fiber layout; and INO pathophysiology.
- Pharmacology (HY): adverse effects of phenytoin, carbamazepine, lamotrigine, and benzodiazepines; plus glaucoma therapy options and adverse effects.
Checkout our Blog on the Ultimate Step 2 Guide for more informations about Study Structure
Watch our video, “USMLE STEP 2 CK in 2 months”.
🧠 Psychiatry
Psychiatry has one of the highest overlaps between Step 1 and Step 2 CK, so most concepts carry over directly. The main basic-science content to cover from step 1 to Step 2 is psychopharmacology, especially drug mechanisms and adverse-effect patterns.
- Mood stabilizers: lithium key adverse effects.
- Antipsychotics: typical/atypical adverse effects and EPS progression; basics of neuroleptic malignant syndrome.
- Antidepressants: SSRI/SNRI/TCA basic mechanisms and essential side effects
- Atypical antidepressants: bupropion (seizure risk) and mirtazapine (sedation + weight gain).
- Substance-related pharmacology: naloxone/naltrexone, methadone and buprenorphine clinical use.
🚽Renal
Renal questions on USMLE Step 2 CK rely heavily on core Step 1 physiology and pathophysiology, especially nephron functions, RAAS regulation, and acid–base basics. Reviewing these foundations makes it easier to interpret kidney injury patterns, electrolyte trends, and classic NBME renal presentations.
- Congenital & structural pathophysiology of Potter sequence, posterior urethral valves, and vesicoureteral reflux.
- Renal physiology basics: diuretics by nephron segment (mechanism → key adverse effects), RAAS physiology, aldosterone/ADH effects, and ACE inhibitor adverse effects.
- Acid–base disorders: core causes of metabolic acidosis and alkalosis, plus understanding Winter’s formula.
- Glomerular & tubular pathophysiology: nephritic vs nephrotic syndromes (PSGN, diabetic nephropathy, amyloidosis) and acute tubular necrosis.
- Urinary basics: kidney stone formation mechanisms and common bacterial causes of cystitis and pyelonephritis.
Watch our video, “How to Study UWorld for USMLE Step 2” to learn proven strategies for mastering the UWorld question bank.
🤰Reproductive
Reproductive questions on USMLE Step 2 CK often depend on core Step 1 developmental genetics and endocrine physiology. Understanding these foundations makes it easier to recognize classic lab patterns, reproductive hormone disorders, and high-yield obstetric and gynecologic presentations on Step 2 CK.
- Development & genetic basics: major teratogenic drugs; twin-to-twin transfusion pathophysiology; and key sex-development disorders including Klinefelter, Turner, androgen insensitivity, and 5α-reductase deficiency (core lab patterns).
- Reproductive endocrine physiology: effects of estrogen and progesterone on the endometrium; hypothalamic–pituitary–gonadal axis basics; pathophysiology behind precocious puberty; and essential physiologic changes during pregnancy.
- High-yield reproductive labs: characteristic hormonal patterns in PCOS, primary ovarian insufficiency, and functional hypothalamic amenorrhea.
- Gestational trophoblastic disease: essential pathophysiology and classic findings in molar pregnancies.
- Male reproductive basics: priapism (pathophysiology + major risk factors), varicocele mechanism, testicular torsion pathophysiology, and testosterone supplementation leading to secondary testicular atrophy.
🚭Respiratory
Respiratory questions on USMLE Step 2 CK rely heavily on core Step 1 lung physiology and pathophysiology, especially gas exchange, lung mechanics, and classic infectious patterns. Understanding these basics makes it easier to interpret PFTs and recognize common pulmonary disorders on NBME exams.
- Development & gas exchange basics: neonatal respiratory distress syndrome (surfactant deficiency pathophys) and the effect of carbon monoxide on oxygen binding/delivery.
- Pulmonary physiology: essential lung volumes/capacities and how they differentiate obstructive vs restrictive patterns.
- Critical respiratory pathophys: ARDS fundamentals; sleep apnea basics (obstructive vs central); pulmonary hypertension; and the major types of pneumothorax.
- Infections: core pneumonia patterns (lobar, bronchopneumonia, interstitial) with high-yield causative bacteria; and the basic mechanism behind lung abscess formation.
- Tumors: key lung cancers with paraneoplastic syndromes and Pancoast tumor involvement causing SVC obstruction.
- Pharmacology (HY): essential asthma medications and their mechanisms; basic differences between first- and second-generation antihistamines.
📉 Biostatistics
Biostatistics on Step 2 CK is essentially an extension of what you learned for Step 1. The core concepts remain the same.
The difference is how Step 2 tests them: questions are more clinical, more data-driven, and often require interpreting tables, survival curves, confidence intervals, and real patient scenarios.
Because Step 2 CK builds directly on Step 1 without introducing brand-new mechanisms, there’s no separate list of “Step 1 topics to review” for biostats. Instead, you should make sure you can:
- Apply the classic Step 1 formulas to clinical vignettes
- Identify bias and confounding in real research scenarios
- Analyze screening test performance based on changing disease prevalence
- Use sensitivity/specificity in patient counseling questions
If your Step 1 biostats foundation is solid, Step 2 CK becomes much more straightforward because the exam simply expects you to use the math and concepts in a more clinical way
Want to master Biostatistics for Step 1, Step 2 CK, and Step 3? Get our high-yield Biostatistics Course click here to start learning!
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🦠Microbiology
Microbiology on USMLE Step 2 CK still depends on core Step 1 mechanisms, especially toxin effects, organism morphology, and key infectious patterns. Reviewing these basics helps you quickly recognize pathogens and predict complications in NBME-style vignettes.
- Key organism groups: high-yield gram-positive, gram-negative, atypical, anaerobic, and encapsulated bacteria: especially those associated with asplenia (Strep pneumoniae, H. influenzae, Neisseria meningitidis).
- Classic morphology & basic identification clues: Staph vs Strep distinctions; Neisseria kidney-shaped diplococci; and acid-fast organisms.
- High-yield toxin-mediated pathophysiology: C. difficile toxins, botulinum toxin, tetanus toxin, diphtheria toxin, pertussis toxin, and Shiga toxin.
- Viral & fungal overlap: EBV vs CMV distinctions; classic endemic fungi (Histoplasma, Blastomyces, Coccidioides); and high-yield yeasts/molds such as Candida and Aspergillus.
- Mycobacteria: tuberculosis pathogenesis and the risk of reactivation with TNF-α inhibitor therapy.
- Spirochetes / STI basics: syphilis testing (RPR/VDRL vs FTA-ABS) and high-yield recognition of major STI pathogens (Chlamydia, N. gonorrhoeae, HSV, Haemophilus ducreyi, Trichomonas).
- Pharmacology (HY side effects only): major antibiotic toxicities including aminoglycoside nephro/ototoxicity, fluoroquinolone tendinopathy/QT prolongation, tetracycline photosensitivity, and TMP-SMX associated hyperkalemia.
🥗 Nutrition
Nutrition topics on USMLE Step 2 CK build directly on Step 1 foundations — vitamin deficiencies, malnutrition syndromes, and metabolic conditions appear regularly in both pediatric and adult vignettes. Knowing the classic deficiency patterns and their clinical presentations makes these questions straightforward.
- Vitamin deficiencies: fat-soluble vitamins (A, D, E, K) absorption requirements, classic deficiency presentations, and toxicity patterns; B-vitamin deficiencies including B1 (Wernicke-Korsakoff), B3 (pellagra), B6 (sideroblastic anemia, peripheral neuropathy), B12 and folate (megaloblastic anemia, neural tube defects).
- Malnutrition syndromes: pathophysiology and distinguishing features of kwashiorkor vs marasmus, especially lab findings and clinical appearance.
- Mineral & trace element deficiencies: zinc deficiency (wound healing, dermatitis, hypogonadism), iron deficiency vs anemia of chronic disease patterns, and iodine deficiency (thyroid implications).
- Malabsorption & nutritional consequences: fat-soluble vitamin deficiency secondary to conditions like Crohn’s, cystic fibrosis, and short bowel syndrome; and the nutritional impact of celiac disease.
- Refeeding syndrome: pathophysiology and key electrolyte shifts, particularly relevant in eating disorder and post-surgical vignettes on Step 2 CK.
- Pharmacology (HY): folate supplementation in pregnancy, thiamine administration before glucose in altered mental status, and vitamin K reversal of warfarin.
Drill these nutrition concepts in clinical vignettes on the Synapse QBank The Match Guy’s tiered, high-yield question bank includes vignette-based nutrition questions designed for the new 2026 USMLE format, with AI chat and integrated flashcards to lock in deficiency patterns, drug-nutrient interactions, and chronic disease scenarios.
Get our free Step 1 & Step 2/3 nutrition PDFs covering the highest-yield concepts most likely to appear on the exam.
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Your Next Step in Step 2 CK Prep
As you move into your Step 2 CK study plan, keep this guide beside you as a quick, targeted reference. Before starting a new system in your Qbank, skim the bullets for that section here, refresh those specific Step 1 mechanisms in your preferred resources, and then jump straight into the questions. This keeps your review focused and prevents you from wasting time on low-yield details.
Use this list to stay grounded, sharpen your clinical reasoning, and make each question block more intuitive. With the right basic-science foundations refreshed at the right time, Step 2 CK becomes far easier to approach.
You now have a clear map of the Step 1 concepts that actually matter: use it strategically as you continue your prep.
If you want a complete, step-by-step breakdown of how to structure your full Step 2 CK study plan, you can check out Dr. Malke Asaad’s video on How to Prepare for USMLE Step 2 CK in 2025.
For personalized Step 2 preparation strategies, high-yield resources, and expert tutoring, explore our Proven USMLE Tutoring packages.
Free high-yield notes for USMLE Step 2 covering essential must-know concepts
You can also bundle these notes with our full course, which explains the notes in-depth and covers additional high-yield concepts. Enroll today for USMLE Step 2 prep.
If you need guidance on your target USMLE scores or have questions on improving your chances of matching into your dream specialty, feel free to schedule a call or text us on WhatsApp for personalized support.
Good luck on your journey to becoming a future physician!
By Mahdi Ahmed
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