Table 3.

Sampling duration and GFR estimates stratified by estimated GFR (eGFR)^a

Sampling Duration	Mean GFR (ml/min/1.73 m2)	95% CIb	Ratio Compared to 5-h GFR	95% CI of Ratio	P
eGFR stratum >30 ml/min/1.73m2
5 h	49.3	44.4 to 54.8
4 h	52.5	47.2 to 58.3	1.06	0.99 to 1.14	0.084
3 h	57.2	51.5 to 63.5	1.16	1.08 to 1.25	<0.001
2.5 h	60.4	54.4 to 67.2	1.23	1.14 to 1.32	<0.001
2 h	66.1	59.5 to 73.4	1.34	1.25 to 1.44	<0.001
eGFR stratum <30 ml/min/1.73m2
5 h	29.1	26.3 to 32.2
4 h	32.0	28.9 to 35.4	1.10	1.03 to 1.18	0.007
3 h	34.5	31.2 to 38.2	1.19	1.11 to 1.27	<0.001
2.5 h	38.2	34.6 to 42.3	1.31	1.23 to 1.41	<0.001
2 h	44.4	40.1 to 49.1	1.53	1.42 to 1.63	<0.001

^aMean GFR calculated using a nominal mixed model with maximal likelihood estimates.

^bCI, confidence interval.