Table 3.

Diagnostic performance of two predicted tests, estimated using the BH4 loading as the gold standard.

	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	Accuracy (%)
AV sum (cut-off: >2)	81.1%	92.5%	90.9%	84.1%	87.01%
BH4-responsiveness-status of the mutations	82.9%	97.3%	97.1%	83.7%	89.74%

PPV: positive predictive value; NPV: negative predictive value; OP: odd product; A: true positive (TP); B: false negative (FN); C: false positive (FP); D: true negative (TN).

Sensitivity = True positive rate (TPR) = A/(A + B) = TP/(TP + FN).

Specificity = True negative rate (TNR) = D/(C + D) = TN/(FP + TN).

PPV = precision = A/(A + C) = TP/(TP + FP).

NPV = TN/(TN + FN).

Accuracy = (A + D)/(A + B + C + D).