Table 2.

Specificity, sensitivity, positive and negative predictive value, and detection rate at different Phe cut-offs.

Number of newborns	37,784
Phe cut-off value (µmol/L)	120	130	140	150	160	170	180	190	200
Recalls (N)	108	41	21	16	12	11	11	9	9
False positive (N)	102	35	15	10	6	5	5	3	3
True positive (N)	6	6	6	6	6	6	6	6	6
False negative (N)	0	0	0	0	0	0	0	0	0
True negative (N)	37,676	37,743	37,763	37,768	37,772	37,773	37,773	37,775	37,775
Detection rate (%)	0.019	0.019	0.019	0.019	0.019	0.019	0.019	0.019	0.019
Sensitivity (%)	100	100	100	100	100	100	100	100	100
Specificity (%)	99.73	99.91	99.96	99.97	99.98	99.99	99.99	99.99	99.99
Positive predictive value (%)	5.56	14.63	28.57	37.50	50.00	54.55	54.55	66.67	66.67
Negative predictive value (%)	100	100	100	100	100	100	100	100	100