Gold standard

GS+

GS−

Test

T+

TP

FP

T−

FN

TN

Sensitivity = TP/(TP + FN)

Specificity = TN/(FP + TN)

Positive predictive value = TP/(TP + FP)

Negative predictive value = TN/(FN + TN)

LR+ = sensitivity/(1 – specificity) = (a/(a + c))/(b/(b + d))

LR− = (1 – sensitivity) / specificity = (c/(a + c))/(d/(b + d))

iNLR = specificity/(1 – sensitivity)

T− = Test negative

T+ = Test positive

FP = False positive

TP = True positive

FN = False negative

TN = True negative

GS− = Gold standard negative

GS+ = Gold standard positive

LR+ = Likelihood ration positive

LR− = Likelihood ration negative