Table 6. B2-microglobulin level cut-off levels that may be used to identify patients with residual renal function measured as GFR.

For various levels of GFR the cut-off β2 microglobulin level was determined that would yield a false positive rate (specificity) of 10%. For each GFR level area under the curve is shown for ROC analyses.

(GFR in ml/min/1.73m2 BSA)	Number of patients with RKF ≥ level in column 1 in cohort	Cut-off β2m microglobulin level (mg/L) for positive test	Sensitivity	Specificity	AUC
1	155	≤24.05	0.7	0.90	0.89
2	130	≤23.65	0.76	0.90	0.92
3	104	≤21.80	0.77	0.90	0.91
4	84	≤20.40	0.75	0.90	0.92
5	64	≤19.05	0.67	0.90	0.91
6	48	≤18.85	0.71	0.90	0.93
7	29	≤18.05	0.83	0.90	0.95
8	18	≤17.45	0.94	0.90	0.96
9	16	≤17.35	0.94	0.90	0.97
10	11	≤16.70	1.00	0.90	0.98

AUC: Area Under the Curve