Probability that a positive test result is truly positive
Expansion
Positive Predictive Value
Purpose
Depends on disease prevalence; higher prevalence increases positive predictive value
Clinical Context
Positive predictive value equals true positives divided by total positives (true plus false). Prevalence-dependent. Screening tests have lower positive predictive value if disease prevalence low.
Related Terms
- Negative predictive value
- Sensitivity
- Specificity
Key Points
- Positive predictive value varies with prevalence; high sensitivity with low specificity gives low positive predictive value if disease rare