| Counts | Disease present | Disease absent | Totals |
|---|---|---|---|
| (+) Test | |||
| (-) Test | |||
| Totals |
| Prevalence (pre-test probability) | Sample size | ||
| Sensitivity | Specificity | ||
| PPV | NPV | ||
| Pretest odds | Odds ratio | ||
| (+) likelihood ratio | (-) likelihood ratio | ||
| post-test odds with (+) | post-test odds with (-) | ||
| Youden Index | Predictive Summary Index | ||
| NND | NNM | ||
| Probabilities | Disease present | Disease absent | Totals |
|---|---|---|---|
| (+) Test | |||
| (-) Test | |||
| Totals | 1.00000 |
| Definitions | |||
|---|---|---|---|
| Prevalence | (TP+FN)/(TP+FN+FP+TN) | p(D) | Probability a random member of the population has disease |
| Sensitivity | TP/(TP+FN) | p(T|D) | Probability of a positive test in a person with disease |
| Specificity | TN/(TN+FP) | p(~T|~D) | Probability of a negative test in a person without disease |
| Positive predictive value (PPV) | TP/(TP+FP) | p(D|T) | Probability of disease in a person with a positive test |
| Negative predictive value (NPV) | TN/(TN+FN) | p(~D|~T) | Probability of no disease in a person with a negative test |
| Odds ratio | (TP*TN)/(FP*FN) | o(D|T)/o(D|~T) | Odds of disease with positive test ÷ Odds of disease with negative test |
| Pretest odds | (TP+FN)/(TN+FP) | p(D)/p(~D) | Odds that disease is present prior to testing |
| (+) Likelihood ratio | TP(TP+FN)/FP(TN+FP) | p(T|D)/p(T|~D) | Odds of positive test in patient with disease |
| (-) Likelihood ratio | FN(TP+FN)/TN(TN+FP) | p(~T|D)/p(~T|~D) | Odds of negative test in patient with disease |
| Post-test odds (+) | TP/FP | p(D|T)/p(~D|T) | Odds of disease when test is (+) |
| Post-test odds (-) | FN/TN | p(D|~T)/p(~D|~T) | Odds of disease when test is (-) |