Table 2.

Performance of Serum IgG4 in discriminating IAC from All CCA in the Test (T) and Validation (V) cohorts

IgG4 Cutoff	Sensitivity (%)		Specificity (%)		PPV (%)		NPV (%)
Cohort	T	V	T	V	T	V	T	V
>140 (1x ULN)	78	64	87	88	70	60	91	89
>280 (2x ULN)	50	34	97	96	86	70	83	83
>560 (4x ULN)	26	17	100	99	100	89	77	80

All CCA (All cases of Cholangiocarcinoma); IAC (IgG4- Associated Cholangitis); PPV (Positive Predictive Value); NPV (Negative Predictive Value); ULN (Upper Limit of Normal); IgG4 unit = mg/dL