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Table 1 Formulae for test metrics used to evaluate the performance of diagnostic tests

From: Urinary ATP and visualization of intracellular bacteria: a superior diagnostic marker for recurrent UTI in renal transplant recipients?

Test Metric Formula
Sensitivity TP/(TP + FN)
Specificity TN/(TN + FP)
Positive Predictive Value (PPV) TP/(TP + FP)
Positive Likelihood Ratio (LR+) Sensitivity/(1-Specificity)
Negative Likelihood Ratio (LR-) (1-Sensitivity)/Specificity
Accuracy (TP + TN)/(TP + TN + FP + FN)
Youden’s Index Sensitivity + Specificity −1
Diagnostic Odds Ratio (DOR) (TP/FN)/(FP/TN)
  1. Key: TP, TN, FP, and FN denote the number of true positives, true negatives, false positives, and false negatives, respectively.