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Table 4 Precision of GFR measurements and time to steady state during CILDI

From: Validation of a continuous infusion of low dose Iohexol to measure glomerular filtration rate: randomised clinical trial

Method B Precision (Plasma clearance)
Subject 95% CI 99% CI 3 SD^ Time to steady state (min) [no. samples]
Healthy Volunteers
1 2.9 3.9 4.5 98 [7]
2 10.4 13.6 15.9 248 [4]
3 2.7 3.6 4.2 126 [6]
4 8.3 10.8 12.7 287 [4]
5 1.3 1.7 2.0 118 [7]
6 3.1 4.0 4.7 127 [6]
7 4.5 6.0 6.9 86 [8]
8 3.5 4.7 5.4 205 [5]
9 4.7 6.2 7.2 110 [7]
10 5.8 7.6 8.9 154 [6]
11 1.0 1.4 1.6 143 [6]
Mean ± SD 4.4 ± 2.9 5.8 ± 3.7 6.7 ± 4.4 155 ± 126
Chronic Kidney Disease
12 6.6 8.7 10.2 555 [3*]
13 17.7 23.2 27.1 598 [3*]
14 15.8 20.8 24.2 508 [3*]
15 6.3 8.3 9.6 327 [4]
16 6.9 9.1 10.6 335 [3]
17 12.5 16.3 19.1 600 [3*]
Mean ± SD 11.0 ± 5.1 14.4 ± 6.6 16.8 ± 7.4 487 ± 65
All Volunteers
Mean ± SD 6.7 ± 4.9 8.8 ± 6.4 10.3 ± 7.4 172 ± 185
  1. Precision of individual GFR measurements was calculated for each subject during CILDI to confidence intervals (CI) of 95% and 99%, and to 3 standard deviations (SD). Precision results are expressed as percentages. ^3SD = 99.7%CI. Theoretical time to steady state (Css) was calculated by drawing a 2-phase exponential decay curve, using Graphpad Prism®, version 5.0d (Graphpad software, Inc.). All samples used after this time was achieved were used, except where Css was >8 h. In these circumstances, the last 3 samples were used (*).