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The formula of the sensitivity, specificity, PPV, and the NPV.
| Pathology results (Gold standard) | Total | |||
|---|---|---|---|---|
| Positive | Negative | |||
| (Cancer group) | (Healthy group) | |||
| Analyzed marker | Positive | a (TP) | b (FP) | a+b |
| Negative | c (FN) | d (TN) | c+d | |
| Total | a+c | b+d | a+b+c+d | |
TP: true positive; FP: false positive; FN: false negative; TN: true negative.
Sensitivity=a/(a+c); specificity =d/(b+d); PPV=a/(a+b); NPV=d/(c+d).
