Diagnostic performance of individual characteristics and anthropometric measurements in detecting elevated serum alanine aminotransferase among children and adolescents

Table 3 The optimal cut-off points and the probability of significant individual parameters for identifying elevated ALAT, separately based on the diagnostic criteria I and II

Parameter	Criterion I (> 30 U/L for boys and > 19 U/L for girls)							Criterion II (> 40 U/L for boys and girls)
Parameter	Cut-off	Accuracy	Sen	Spe	Youden index	PPV	NPV	Cut-off	Accuracy	Sen	Spe	Youden index	PPV	NPV
Age	13.7 years	44.0	76.2^a	41.5	17.7	9.0	95.8	13.7 years	41.8	78.7^a	40.8	19.5	3.6	98.6
Height	164.0 cm	49.0	72.3	47.3	19.5	9.5	95.7	169.5 cm	67.3	61.9	67.5	29.4	5.0	98.5
Weight	67.8 kg	87.1^a	55.0	89.5^a	44.6	28.6^a	96.3	68.9 kg	88.9^a	69.5	89.5^a	59.0^a	15.6^a	99.1
BMI	22.6 kg/m²	82.9	61.6	84.5	46.1^a	23.3	96.6^a	22.3 kg/m²	80.8	77.2	80.9	58.0	10.1	99.2^a
BMI-z	0.95	79.1	60.1	80.5	40.6	19.1	96.4	1.25	84.3	70.1	84.7	54.7	11.3	99.0

The optimal cut-off points were based on the maximum Youden index for each parameter; the probability of parameters for identifying elevated ALAT is expressed as %
Sen Sensitivity, Spe Specificity, PPV Positive predictive value, NPV Negative predictive value
^a The best performance for each conventional diagnostic test index

ISSN: 1471-2431