USMLE purpose: Use prevention-level keywords and 2×2 table logic to avoid getting lost in long stems.

How to use this page

1. Start with the prevention table and memorize primary = prevents, secondary = screens, tertiary = treats.
2. Review the diagnostic-test box before doing PPV questions.
3. Work the practice questions before opening the answer explanations.
4. Use the transcript only if you want to verify Randy’s original wording.

• Episode metadata

One-liner

This episode focuses on quick recognition: primary prevents, secondary screens, tertiary treats; then use the diagnostic-test box to solve predictive value problems.

Prevention quick table

Diagnostic-test box

Exam pattern recognition

• “Prevents disease before it exists” → primary prevention.
• “Screening for occult blood” → secondary prevention.
• “Incidence/new cases decreased by…” → primary prevention.
• “Patient tests positive; what is chance they truly have disease?” → PPV.
• “New drug must reduce recurrence by at least 40%” → use logic against the baseline risk.

Common traps