USMLE Step 2 CK Key Vocabulary
Essential terms and definitions you must know before exam day.
Key Vocabulary
Number needed to treat (NNT)
1 / absolute risk reduction. How many patients must be treated to prevent one bad outcome.
Likelihood ratio
How much a test result changes pre-test probability. LR+ > 10 strongly suggests disease; LR− < 0.1 strongly rules out.
qSOFA
Quick sepsis screen: RR ≥22, altered mental status, SBP ≤100. ≥2 = high risk.
GRACE score
Risk stratification for ACS — predicts in-hospital and 6-month mortality.
CHA₂DS₂-VASc
Stroke risk in atrial fibrillation. Score ≥2 (men) / ≥3 (women) → anticoagulation.
Vocabulary Study Tips
- 1.UWorld is again the gold standard — do all 4,000+ Qs at least once.
- 2.Watch Online MedEd or Boards & Beyond clinical sciences during clerkships.
- 3.Take NBME CCS practice exams every 1–2 weeks in dedicated prep.
- 4.Prioritize: internal medicine, surgery, pediatrics, OB/GYN, psychiatry — 80% of the test.