Розподіл результатів тесту гіпотетичного тесту на естеразу лейкоцитів у когорті з 1000 жінок із передбачуваною 5% поширеністю ІСШ
Results | Disease Present | Disease Absent | Total Patients |
|---|---|---|---|
Test positive | True positive (TP) 36 patients (71% of 50) | False positive (FP) 144 patients (950 −806) | 180 patients with a positive test |
Test negative | False negative (FN) 14 patients (50 −36) | True negative (TN) 806 patients (85% of 950) | 820 patients with a negative test |
Total patients | 50 patients with UTI (assumed) | 950 patients without UTI (assumed) | 1000 patients |
Positive predictive value (PPV) = TP/(all with a positive test) = TP/(TP + FP) = 36/(36 + 144) = 20%. Negative predictive value (NPV) = TN/(all with a negative test) = TN/(TN + FN) = 806/(806 + 14) = 98%. Positive likelihood ratio (LR+) = sensitivity/(1 − specificity) =0.71/(1 − 0.85) =4.73. Negative likelihood ratio (LR-) = (1 − sensitivity)/specificity = (1 − 0.71)/0.85 = 0.34. UTI = urinary tract infection | |||