Table 3. Serum Creatinine Medians by Gestational Age Group and Week of Life 	
Week of Life	N Infants	Median SCr, mg/dL (IQR)	95% BCa CI	
22-24 weeks	
1	549	0.88 (0.77-1.02)	[0.86-0.90]	
2	680	0.80 (0.65-1.02)	[0.77-0.80]	
3	740	0.68 (0.55-0.90)	[0.65-0.70]	
4	819	0.59 (0.46-0.75)	[0.56-0.60]	
5	873	0.49 (0.39-0.64)	[0.47-0.50]	
6	891	0.42 (0.35-0.53)	[0.41-0.44]	
7	871	0.39 (0.32-0.48)	[0.38-0.40]	
8	867	0.35 (0.30-0.42)	[0.35-0.36]	
9	847	0.33 (0.28-0.40)	[0.32-0.32]	
10	830	0.30 (0.26-0.36)	[0.30-0.31]	
11	831	0.30 (0.25-0.35)	[0.29-0.30]	
12	843	0.28 (0.23-0.33)	[0.28-0.29]	
13	845	0.27 (0.22-0.32)	[0.26-0.26]	
14	818	0.26 (0.21-0.30)	[0.25-0.26]	
15	797	0.24 (0.20-0.30)	[0.24-0.25]	
16	766	0.23 (0.20-0.29)	[0.23-0.23]	
25-27 weeks	
1	961	0.83 (0.72-0.95)	[0.80-0.84]	
2	1121	0.65 (0.54-0.80)	[0.63-0.66]	
3	1238	0.56 (0.46-0.70)	[0.55-0.57]	
4	1329	0.49 (0.40-0.60)	[0.48-0.50]	
5	1343	0.42 (0.35-0.50)	[0.41-0.43]	
6	1373	0.38 (0.31-0.44)	[0.37-0.38]	
7	1351	0.34 (0.29-0.41)	[0.34-0.35]	
8	1299	0.32 (0.27-0.38)	[0.31-0.32]	
9	1291	0.30 (0.26-0.36)	[0.30-0.30]	
10	1216	0.28 (0.23-0.33)	[0.28-0.29]	
11	1207	0.26 (0.21-0.30)	[0.25-0.26]	
12	1184	0.25 (0.20-0.30)	[0.25-0.26]	
13	1094	0.24 (0.20-0.29)	[0.23-0.24]	
14	1008	0.23 (0.19-0.28)	[0.23-0.24]	
15	935	0.23 (0.19-0.28)	[0.22-0.23]	
16	848	0.23 (0.19-0.27)	[0.22-0.23]	
28-30 weeks	
1	1088	0.76 (0.66-0.89)	[0.75-0.78]	
2	1160	0.58 (0.48-0.69)	[0.57-0.59]	
3	1139	0.48 (0.40-0.57)	[0.47-0.49]	
4	1115	0.41 (0.35-0.49)	[0.40-0.42]	
5	1069	0.37 (0.30-0.42)	[0.36-0.38]	
6	989	0.32 (0.28-0.39)	[0.31-0.32]	
7	923	0.30 (0.25-0.36)	[0.29-0.29]	
8	851	0.28 (0.24-0.33)	[0.27-0.28]	
9	761	0.26 (0.21-0.30)	[0.25-0.26]	
10	686	0.24 (0.20-0.29)	[0.23-0.25]	
11	610	0.24 (0.19-0.28)	[0.23-0.24]	
12	522	0.23 (0.20-0.28)	[0.22-0.23]	
13	478	0.23 (0.19-0.27)	[0.22-0.23]	
14	409	0.22 (0.18-0.27)	[0.21-0.22]	
15	339	0.22 (0.19-0.27)	[0.21-0.22]	
16	316	0.22 (0.18-0.26)	[0.20-0.22]	
31-33 weeks	
1	1877	0.71 (0.60-0.82)	[0.70-0.72]	
2	1561	0.50 (0.41-0.60)	[0.50-0.52]	
3	1294	0.42 (0.34-0.50)	[0.41-0.43]	
4	1119	0.35 (0.29-0.42)	[0.34-0.35]	
5	970	0.31 (0.25-0.38)	[0.30-0.31]	
6	834	0.28 (0.22-0.34)	[0.28-0.29]	
7	702	0.27 (0.21-0.32)	[0.25-0.27]	
8	631	0.25 (0.20-0.31)	[0.23-0.24]	
9	532	0.25 (0.20-0.30)	[0.23-0.25]	
10	476	0.23 (0.20-0.30)	[0.22-0.24]	
11	428	0.23 (0.20-0.30)	[0.22-0.24]	
12	368	0.23 (0.18-0.28)	[0.22-0.24]	
13	326	0.22 (0.19-0.29)	[0.22-0.24]	
14	282	0.22 (0.19-0.28)	[0.21-0.24]	
15	258	0.22 (0.18-0.28)	[0.20-0.22]	
16	231	0.22 (0.18-0.28)	[0.20-0.22]	
34-36 weeks	
1	4890	0.64 (0.52-0.78)	[0.63-0.64]	
2	3135	0.43 (0.35-0.53)	[0.42-0.44]	
3	2217	0.35 (0.29-0.43)	[0.34-0.36]	
4	1740	0.30 (0.25-0.39)	[0.30-0.31]	
5	1312	0.28 (0.22-0.35)	[0.28-0.29]	
6	1089	0.26 (0.20-0.33)	[0.26-0.27]	
7	880	0.25 (0.20-0.31)	[0.24-0.24]	
8	749	0.24 (0.20-0.30)	[0.23-0.24]	
9	639	0.23 (0.19-0.30)	[0.22-0.23]	
10	572	0.23 (0.19-0.30)	[0.22-0.23]	
11	491	0.22 (0.18-0.30)	[0.22-0.23]	
12	448	0.22 (0.18-0.30)	[0.20-0.22]	
13	385	0.23 (0.17-0.30)	[0.21-0.23]	
14	343	0.21 (0.16-0.28)	[0.20-0.21]	
15	303	0.22 (0.17-0.28)	[0.20-0.22]	
16	269	0.23 (0.17-0.30)	[0.21-0.24]	
>=37 weeks	
1	13990	0.58 (0.47-0.72)	[0.58-0.59]	
2	7306	0.39 (0.31-0.47)	[0.39-0.40]	
3	4332	0.32 (0.26-0.40)	[0.32-0.33]	
4	2905	0.30 (0.23-0.36)	[0.29-0.30]	
5	2196	0.27 (0.21-0.34)	[0.27-0.28]	
6	1668	0.26 (0.20-0.32)	[0.25-0.26]	
7	1339	0.25 (0.20-0.31)	[0.24-0.26]	
8	1085	0.24 (0.20-0.30)	[0.24-0.25]	
9	898	0.24 (0.19-0.30)	[0.23-0.24]	
10	761	0.23 (0.19-0.29)	[0.22-0.23]	
11	636	0.23 (0.19-0.29)	[0.22-0.23]	
12	542	0.23 (0.19-0.29)	[0.22-0.23]	
13	481	0.23 (0.18-0.30)	[0.22-0.23]	
14	423	0.22 (0.18-0.29)	[0.21-0.22]	
15	375	0.22 (0.18-0.30)	[0.20-0.22]	
16	319	0.22 (0.18-0.29)	[0.20-0.22]	
Values are median (interquartile range). 95% BCa CI = bias-corrected accelerated bootstrapped confidence interval for the median (1000 replications).