USMLE Step 3 CCS cases span roughly eight core specialties, with internal medicine dominating at about 40-50% of the 13 cases you will see on exam day. The remaining cases are split across emergency medicine, surgery, obstetrics/gynecology, pediatrics, psychiatry, neurology, and preventive medicine. Knowing the specialty distribution, the most common presentations within each discipline, and the key orders the scoring algorithm expects gives you a significant strategic advantage.
How Many CCS Cases Are on Step 3, and How Are They Divided by Specialty?
Step 3 Day 2 includes exactly 13 CCS cases: seven cases at 20 minutes each and six cases at 10 minutes each, for a total of 200 minutes of simulation time. The USMLE Step 3 Content Outline does not publish a fixed specialty distribution, but the exam blueprint and historical test-taker reports reveal a consistent pattern. Internal medicine cases make up the largest share, while surgical, OB/GYN, psychiatry, and pediatrics cases appear in smaller but predictable numbers.
According to the NBME Step 3 content specifications, CCS cases are designed to test the "application of clinical science in the context of patient management." This means every case, regardless of specialty, is scored on the same pillars: diagnosis, workup, treatment, monitoring, patient location, and avoidance of harmful orders.
The table below shows the approximate specialty distribution based on reported exam experiences and the USMLE content blueprint:
| Specialty | Estimated Cases per Exam | Case Length | Weight on CCS Score |
|---|---|---|---|
| Internal Medicine | 5-7 | Mostly 20 min | ~40-50% |
| Emergency Medicine | 2-3 | 20 min | ~15-20% |
| Surgery | 1-2 | 20 min | ~8-12% |
| OB/GYN | 1-2 | 10-20 min | ~8-10% |
| Pediatrics | 1-2 | 10-20 min | ~8-10% |
| Psychiatry | 1 | 10-20 min | ~5-8% |
| Neurology | 0-1 | 20 min | ~5-8% |
| Preventive / Outpatient | 1-2 | 10 min | ~5-8% |
Note: Neurology and preventive medicine cases sometimes overlap with internal medicine. The USMLE does not label cases by specialty, so the categorization above reflects the primary clinical domain being tested. For a full breakdown of the Step 3 CCS format, timing, and case count, see our format guide.
What Internal Medicine Cases Show Up Most on CCS?
Internal medicine dominates the CCS section because it is the broadest discipline tested on Step 3. Expect five to seven cases covering cardiology, pulmonology, endocrinology, gastroenterology, nephrology, and infectious disease. These cases are almost always 20-minute simulations set in the emergency department or inpatient ward.
Most common internal medicine CCS presentations:
- Acute Coronary Syndrome (STEMI/NSTEMI): ECG, serial troponins, aspirin, heparin, beta-blocker, statin, cardiology consult, cath lab activation for STEMI
- Diabetic Ketoacidosis: IV fluids first, then insulin drip after confirming potassium above 3.3, serial BMPs, fingerstick glucose every hour, ICU admission
- Sepsis / Septic Shock: Blood cultures before antibiotics, 30 mL/kg crystalloid bolus, broad-spectrum antibiotics within the first simulated hour, vasopressors if refractory hypotension
- Congestive Heart Failure Exacerbation: IV furosemide, BNP, echocardiogram, daily weights, fluid restriction, ACE inhibitor once stabilized
- COPD Exacerbation: Bronchodilators, systemic steroids, antibiotics if purulent sputum, ABG, chest X-ray, supplemental oxygen titrated to SpO2 88-92%
- Acute Pancreatitis: NPO, aggressive IV fluids, lipase, CT abdomen if no improvement at 48-72 hours, pain management with IV opioids
- Acute Kidney Injury: Identify prerenal vs. intrinsic vs. postrenal, IV fluids for prerenal, urinalysis with microscopy, renal ultrasound, nephrology consult if indicated
For a deeper look at the highest-yield cases across all specialties, see our Top 10 CCS Cases You Must Master for Step 3.
What Emergency Medicine Cases Should I Expect on Step 3 CCS?
Emergency medicine CCS cases are almost always 20-minute cases that begin with a critically ill patient in the ED. The scoring algorithm is most time-sensitive in these scenarios, meaning you will lose points for every minute of delay on critical interventions. Expect two to three cases that test your ability to stabilize a patient, order the right workup, and initiate treatment simultaneously.
High-yield emergency presentations:
- Pulmonary Embolism: CT angiography, heparin anticoagulation, hemodynamic support, thrombolytics for massive PE with hemodynamic instability
- Stroke (Ischemic): Non-contrast CT head stat, check glucose, tPA if within the window and no contraindications, neurology consult, ICU admission
- GI Bleeding (Upper): Two large-bore IVs, type and crossmatch, PPI drip, GI consult for endoscopy, transfuse if hemoglobin is below 7
- Anaphylaxis: IM epinephrine immediately, IV fluids, supplemental oxygen, diphenhydramine, methylprednisolone, monitor for biphasic reaction
- Trauma / Surgical Abdomen: ABCs, FAST exam, CT abdomen/pelvis with contrast, surgical consult, NPO if operative management anticipated
The key to scoring well on emergency cases is front-loading your orders. Place emergency stabilization orders, labs, and imaging in the first one to two minutes of simulated time. The scoring algorithm rewards speed in these scenarios more than in any other specialty. Our CCS cheat sheet has order sets you can memorize for these high-acuity presentations.
What Surgery Cases Appear on Step 3 CCS?
Surgery cases on Step 3 CCS are not asking you to perform an operation. They are testing whether you can recognize a surgical diagnosis, stabilize the patient, order the appropriate preoperative workup, and consult the correct surgical service. Expect one to two surgery-related cases, typically a 20-minute scenario.
Common surgical CCS presentations:
- Acute Appendicitis: CT abdomen/pelvis, CBC, BMP, NPO, IV fluids, IV antibiotics, general surgery consult
- Cholecystitis: Right upper quadrant ultrasound, CBC, LFTs, lipase, NPO, IV fluids, IV antibiotics, surgical consult for cholecystectomy
- Small Bowel Obstruction: Abdominal X-ray (upright and supine), CT abdomen, NGT decompression, NPO, IV fluids, surgical consult
- Ectopic Pregnancy (surgical overlap): Beta-hCG, transvaginal ultrasound, type and crossmatch, OB/GYN consult, hemodynamic monitoring
The critical scoring points in surgical cases are: (1) recognizing the need for surgical consultation early, (2) keeping the patient NPO, and (3) avoiding delays in imaging. A common mistake is ordering a CT scan and then waiting for results before calling the surgeon. On CCS, you should place the surgical consult order at the same time as the confirmatory imaging.
What OB/GYN Cases Are Tested on CCS?
OB/GYN cases appear in one to two of the 13 CCS simulations. These cases often catch test-takers off guard because many residents have limited ongoing obstetric experience. The good news is that the OB/GYN CCS cases tend to test a small set of well-defined clinical scenarios.
Most common OB/GYN CCS presentations:
- Preeclampsia / Eclampsia: IV magnesium sulfate, antihypertensives (labetalol or hydralazine), CBC, BMP, LFTs, urine protein, fetal monitoring, OB consult for delivery planning
- Ectopic Pregnancy: Beta-hCG, transvaginal ultrasound, Rh typing, OB/GYN consult, surgical management if ruptured
- Placental Abruption / Previa: Type and crossmatch, continuous fetal monitoring, IV access, OB consultation, delivery based on severity
- Postpartum Hemorrhage: Uterine massage, IV oxytocin, fluid resuscitation, type and crossmatch, CBC
The scoring algorithm for OB/GYN cases particularly penalizes failure to order fetal monitoring in pregnant patients and failure to check Rh status for bleeding in pregnancy. These are often the "easy points" that test-takers miss.
What Pediatrics Cases Should I Prepare For?
Pediatrics cases appear one to two times across the 13 CCS simulations. They are often 10-minute outpatient cases (well-child visits, asthma management) but can also be 20-minute acute presentations (febrile seizure, bronchiolitis, meningitis). The CCS scoring algorithm adjusts expected orders for age-appropriate care.
High-yield pediatrics CCS presentations:
- Febrile Seizure: Rectal temperature, CBC, BMP, blood culture, urinalysis, lumbar puncture if under 12 months or complex features, reassurance and education for simple febrile seizures
- Bronchiolitis: Nasal suctioning, pulse oximetry, supportive care, oxygen if SpO2 below 90%, no routine antibiotics or bronchodilators
- Pediatric Asthma Exacerbation: Albuterol nebulizer, ipratropium, systemic corticosteroids, oxygen, chest X-ray, peak flow monitoring
- Well-Child Visit: Age-appropriate immunizations, developmental screening, growth chart review, anticipatory guidance, safety counseling
- Meningitis (Pediatric): Blood cultures, lumbar puncture, empiric antibiotics (ceftriaxone plus vancomycin), dexamethasone, ICU admission
Pediatric cases reward you for ordering age-appropriate medication doses and recognizing when to not intervene (e.g., bronchiolitis management is supportive). Ordering unnecessary antibiotics in a viral illness counts against you.
What Psychiatry Cases Come Up on CCS?
Psychiatry typically appears as one case among the 13 CCS simulations. Psychiatry CCS cases often confuse test-takers because the management approach differs substantially from medical or surgical cases. The scoring algorithm still tracks orders, timing, and patient safety, but the "treatment" often involves specific medications, safety assessments, and disposition planning rather than labs and imaging.
Common psychiatry CCS presentations:
- Acute Psychosis / Agitation: Safety assessment, urine drug screen, BMP, CBC, TSH, CT head (to rule out organic causes), antipsychotic medication (haloperidol or olanzapine), 1:1 observation, psychiatry consult
- Suicidal Ideation / Attempt: Immediate safety precautions (1:1 sitter, remove sharps), toxicology screen, acetaminophen level, salicylate level, ECG, psychiatry consult, inpatient psychiatric admission
- Major Depressive Episode (outpatient): PHQ-9 screening, TSH, SSRI initiation, safety assessment (suicidal ideation screening), follow-up in 2-4 weeks, counseling referral
- Alcohol Withdrawal: CIWA protocol, benzodiazepines (chlordiazepoxide or lorazepam), thiamine before glucose, folate, BMP, CBC, LFTs, magnesium level
The biggest mistake on psychiatry CCS cases is skipping the medical workup. Every psychiatric presentation requires you to rule out organic causes first: drug screen, metabolic panel, thyroid studies, and sometimes brain imaging. The scoring algorithm specifically checks for this.
What Preventive Medicine and Outpatient Cases Look Like on CCS
Preventive medicine and outpatient cases are typically the 10-minute simulations. They test your knowledge of screening guidelines, health maintenance, and chronic disease management. These cases feel easier than the acute inpatient scenarios, but test-takers often lose points by forgetting routine orders.
Common outpatient/preventive CCS presentations:
- Health Maintenance Visit: Age-appropriate cancer screening (colonoscopy, mammogram, Pap smear), lipid panel, HbA1c or fasting glucose, immunization review, counseling (smoking cessation, diet, exercise)
- Hypertension Management: BMP, urinalysis, ECG, lipid panel, HbA1c, initiate medication per guidelines, follow-up in 4-6 weeks
- Diabetes Follow-Up: HbA1c, BMP, lipid panel, urine microalbumin, foot exam, eye exam referral, medication adjustment
- Chronic Disease Management: Medication reconciliation, screening for complications, referrals for subspecialty care, lifestyle counseling
The scoring algorithm checks that you order every guideline-recommended screening test for the patient's age and risk factors. Missing a colon cancer screening in a 50-year-old or a mammogram in a 45-year-old costs real points even though the case may not be "about" cancer screening.
How Should I Prioritize Specialties When Studying for CCS?
Prioritize internal medicine and emergency medicine first because they account for roughly 60-70% of your CCS cases and carry the heaviest scoring weight. After those are solid, move to surgery, OB/GYN, and pediatrics. Psychiatry and preventive medicine should come last, not because they are unimportant, but because their case patterns are narrower and easier to learn quickly.
Here is a suggested study allocation for a 4-week CCS study plan:
| Week | Focus | Cases to Practice |
|---|---|---|
| 1 | Internal Medicine (Cardiology, Pulm, Endo) | ACS, CHF, DKA, COPD, Sepsis |
| 2 | EM + Surgery + GI | PE, Stroke, GI Bleed, Appendicitis, Pancreatitis |
| 3 | OB/GYN + Peds + Psych | Preeclampsia, Ectopic, Febrile Seizure, Psychosis |
| 4 | Mixed review + Preventive | Full-length timed practice, health maintenance |
The most efficient way to build specialty-specific CCS skills is timed simulation practice. MasterCCS offers 50+ cases across all tested specialties with real-time scoring feedback, so you can identify which specialties need more work before exam day. If you are weighing different practice tools, our comparison of MasterCCS vs. other platforms breaks down the differences.
What Orders Does the Scoring Algorithm Track Across All Specialties?
Regardless of specialty, the CCS scoring algorithm evaluates the same core dimensions for every case. Understanding this helps you build a universal approach that works whether the case is cardiology, surgery, or psychiatry.
The USMLE CCS scoring framework evaluates:
- Diagnostic workup: Did you order the right labs and imaging to confirm the diagnosis?
- Treatment: Did you initiate the correct treatment in a timely manner?
- Monitoring: Did you order follow-up labs, vitals, and reassessments?
- Location and activity: Did you place the patient in the correct setting (ICU, ward, outpatient) with appropriate activity restrictions?
- Avoidance of harmful orders: Did you avoid contraindicated medications, unnecessary invasive procedures, or inappropriate tests?
- Timing: Were time-sensitive orders placed early enough?
Across all specialties, the universal order set of vital signs, IV access, continuous monitoring, appropriate labs (CBC, BMP, urinalysis), and physical exam should be placed within the first two minutes. From there, each specialty has its own critical orders. Use our CCS order sets cheat sheet to build muscle memory for the specialty-specific additions. For a complete overview of CCS preparation, see our complete guide to USMLE Step 3 CCS cases.
Frequently Asked Questions
How many specialties are tested on Step 3 CCS?
Step 3 CCS cases cover approximately eight core specialty areas: internal medicine, emergency medicine, surgery, OB/GYN, pediatrics, psychiatry, neurology, and preventive/outpatient medicine. Internal medicine makes up the largest share at roughly 40-50% of the 13 cases. The USMLE does not officially label cases by specialty, but each case maps to a primary clinical domain.
Is there a fixed number of cases per specialty on every exam?
No. The USMLE uses a semi-randomized case selection process, so the exact number of cases per specialty varies between test-takers. However, internal medicine cases are always the most common, and you will almost certainly see at least one OB/GYN, one pediatrics, and one psychiatry or preventive medicine case. The overall distribution is constrained by the Step 3 content specifications.
Can I get a CCS case from a specialty I did not rotate through?
Yes. Step 3 tests general medical knowledge expected of any physician entering independent practice, regardless of your chosen residency specialty. You may encounter OB/GYN cases as an internal medicine resident or cardiology cases as a psychiatry resident. The cases test management principles, not subspecialty expertise.
Are surgery CCS cases asking me to perform a procedure?
No. Surgery CCS cases test whether you can recognize a surgical diagnosis, stabilize the patient, order the correct preoperative workup, and consult the appropriate surgical service. You will never be asked to describe a surgical technique. The scoring algorithm rewards early surgical consultation and appropriate pre-operative preparation.
Which specialty has the hardest CCS cases?
Most test-takers report that emergency medicine cases are the hardest because they are the most time-sensitive. Delays of even one to two simulated minutes on critical orders like tPA for stroke or heparin for PE can result in significant point deductions. Psychiatry cases are often rated as the most unfamiliar because the management approach differs from standard medical cases.
Do outpatient CCS cases matter as much as inpatient ones?
Yes. Every CCS case contributes equally to your overall CCS score on a case-by-case basis. A 10-minute outpatient health maintenance case is scored just as rigorously as a 20-minute ICU sepsis case. Outpatient cases test different skills, particularly preventive screening, chronic disease management, and counseling, but the points are real.
How do I practice CCS cases for specialties I am weak in?
The most effective approach is targeted simulation practice. Identify which specialties you struggled with during clinical rotations and prioritize those in your study plan. Platforms like MasterCCS let you filter cases by specialty so you can drill your weak areas with timed, scored simulations. Even two to three practice cases per specialty is enough to learn the core order patterns.
Should I study CCS cases differently than MCQ material by specialty?
Yes. MCQ preparation focuses on diagnosis and recognition, while CCS preparation focuses on management and execution. You may know the diagnostic criteria for preeclampsia from MCQ study, but CCS requires you to actually order the magnesium sulfate, antihypertensives, fetal monitoring, and labs in the right sequence and at the right time. Practicing with interactive simulations bridges this gap far more effectively than passive review.