Table 7.

Precision of GFR as a function of sampling durationa

Sampling DurationMean GFR CV (%)95% CIDifference from 10-h GFR95% CI of DifferenceP
10 h1.671.38 to 2.01
9 h1.811.50 to 2.181.090.93 to 1.27>0.2
8 h2.061.71 to 2.481.241.06 to 1.440.007
7 h2.381.98 to 2.871.431.23 to 1.67<0.001
6 h2.852.37 to 3.431.711.47 to 1.99<0.001
5 h3.482.89 to 4.192.091.79 to 2.44<0.001
4 h4.313.58 to 5.192.592.22 to 3.02<0.001
3 h4.864.01 to 5.892.912.48 to 3.42<0.001
2.5 h6.115.08 to 7.363.673.15 to 4.28<0.001
2 h7.075.87 to 8.514.243.63 to 4.95<0.001
  • a Mean GFR coefficient of variation (CV) calculated using a nominal mixed model with log-transformed CV using maximal likelihood estimates.