Input Parameters
Probability of testing positive when disease is present
Probability of testing negative when disease is absent
Proportion of population with the disease
Calculated Statistics
Positive Predictive Value (PPV)
--
Negative Predictive Value (NPV)
--
False Positive Rate (FPR)
--
False Negative Rate (FNR)
--
Accuracy
--
Likelihood Ratio (+)
--
Likelihood Ratio (-)
--
2×2 Contingency Table (per 10,000 people)
| Disease Present | Disease Absent | Total | |
|---|---|---|---|
| Test Positive | -- | -- | -- |
| Test Negative | -- | -- | -- |
| Total | -- | -- | 10,000 |
Key Formulas
PPV = (Sensitivity × Prevalence) / (Sensitivity × Prevalence + (1 - Specificity) × (1 - Prevalence))
NPV = (Specificity × (1 - Prevalence)) / (Specificity × (1 - Prevalence) + (1 - Sensitivity) × Prevalence)
Accuracy = Sensitivity × Prevalence + Specificity × (1 - Prevalence)
LR+ = Sensitivity / (1 - Specificity)
LR- = (1 - Sensitivity) / Specificity