Medical Test Paradox & Bayes Screening Laboratory

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🎙️ OVERVIEW AUDIO GUIDE Introduction

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Positive Predictive Value (PPV) P(Disease | Positive)

16.1%

10 True / 62 Total (+)
83.9% False Alarms

True Positives TP

10 / 1,000

Has disease & tested (+)

False Positives FP

50 / 1,000

Healthy, but tested (+)

False Negatives FN

0 / 1,000

Has disease, missed (-)

True Negatives TN

940 / 1,000

Healthy & tested (-)

🦠 Disease Prevalence 1.0% (10 in 1,000)

🎯 Sensitivity (True Pos Rate) 95.0%

🛡️ Specificity (True Neg Rate) 95.0%

Clinical Screening Scenarios

🔬 Rare Screening Trap PPV ≈ 16%

🧬 Ultra-Rare Biopsy PPV ≈ 17%

🏥 Symptomatic Referral PPV ≈ 77%

🧪 Rapid Antigen Test PPV ≈ 57%