Table 5.

 Sensitivity and specificity of total bile acid concentration measurements in prediction of extrahepatic biliary atresia. Positive predictive value (PPV) and negative predictive value (NPV) of test, assuming prevalence of extrahepatic biliary atresia of 1 in 10 000 or 1 in 20 000

Cut off (μmol/l)	% Sensitivity (95% CI)	% Specificity (95% CI)	Prevalence of extrahepatic biliary atresia
			1 in 10 000			1 in 20 000
			PPV %	NPV %		PPV %	NPV %
25.0	85.3 (75.5 to 92.0)	94.0 (92.3 to 95.3)	0.14	100.00		0.07	100.00
30.0	78.7 (68.1 to 86.9)	96.3 (94.9 to 97.4)	0.21	100.00		0.11	100.00
35.0	70.5 (59.4 to 79.9)	97.8 (96.7 to 98.6)	0.32	100.00		0.16	100.00
48.5	50.8 (39.6 to 62.0)	99.0 (98.2 to 99.5)	0.53	100.00		0.26	100.00
67.0	21.3 (13.1 to 31.9)	99.5 (98.7 to 99.8)	0.39	99.99		0.19	100.00
79.0	9.8 (4.4 to 18.7)	100.0 (99.6 to 100.0)	100.00	99.99		100.00	100.00