Table 2.

ROC curve performance and cut-off characteristics for detecting IgG <6 g/L in the overall cohort, the adult, and the pediatric groups.

Patient group	AUC	AUC 95% CI	Cut-off	Cut-off 95% CI	Sensitivity	Specificity	Youden’s Index	Cases below cut-off n (%)
Calculated Globulin
Overall cohort n=980	0.88	0.85 – 0.92	22.00	21.25 – 24.95	0.80	0.87	0.67	205 (21%)
Adult group n=762	0.89	0.86- 0.92	22.25	21.95 – 25.45	0.79	0.86	0.65	161 (21%)
Pediatric group n=218	0.81	0.69 – 0.99	24.15	21.05 – 24.25	0.81	0.79	0.60	40 (18%)
Gammaglobulins
Overall cohort n=980	0.94	0.93 – 0.97	8.9	8.80 – 9.25	0.96	0.88	0.87	180 (18%)
Adult group n=762	0.93	0.91 – 0.98	8.9	8.80 – 9.25	0.95	0.89	0.84	150 (20%)
Pediatric group n=65	0.98	0.95 – 1.00	8.9	6.34 - 9.13	1.00	0.84	0.84	22 (34%)

AUC, Area Under the Curve; CI, Confidence Interval; n, number of patients.