Template:DiagnosticTesting Example
| Patients with bowel cancer (as confirmed on endoscopy) | ||||
| Condition positive | Condition negative | |||
| Fecal occult blood screen test outcome |
Test outcome positive |
True positive (TP) = 20 |
False positive (FP) = 180 |
Positive predictive value = TP / (TP + FP)
= 20 / (20 + 180) = 10% |
| Test outcome negative |
False negative (FN) = 10 |
True negative (TN) = 1820 |
Negative predictive value = TN / (FN + TN)
= 1820 / (10 + 1820) ≈ 99.5% | |
| Sensitivity = TP / (TP + FN)
= 20 / (20 + 10) ≈ 67% |
Specificity = TN / (FP + TN)
= 1820 / (180 + 1820) = 91% | |||