Table 2.

Serum levels of diverse uremic toxins by CKD stage (mg/dl)

	CKD Stage
	2	3	4	5
Creatinine	1.14 ± 0.18	1.52 ± 0.32	2.85 ± 0.96	5.30 ± 1.93
SDMA	0.049 ± 0.017	0.071 ± 0.037	0.115 ± 0.075	0.208 ± 0.065
ADMA	0.057 ± 0.008	0.065 ± 0.010	0.069 ± 0.016	0.076 ± 0.015
Uric acid	7.17 ± 2.33	8.07 ± 1.89	8.33 ± 2.13	8.98 ± 2.66
IS
total	0.15 ± 0.06	0.26 ± 0.14	0.46 ± 0.28	0.92 ± 0.65
free	0.032 ± 0.005	0.03 ± 0.004	0.04 ± 0.01	0.06 ± 0.03
HA
total	0.45 ± 0.16	0.43 ± 0.25	0.59 ± 0.43	0.91 ± 0.46
free	0.28 ± 0.12	0.26 ± 0.12	0.35 ± 0.19	0.53 ± 0.24
pCS
total	0.59 ± 0.33	1.03 ± 0.67	1.68 ± 1.34	2.91 ± 1.67
free	0.028 ± 0.032	0.03 ± 0.03	0.08 ± 0.08	0.19 ± 0.12
IAA
total	0.06 ± 0.03	0.09 ± 0.04	0.10 ± 0.04	0.14 ± 0.89
free	0.023 ± 0.002	0.030 ± 0.004	0.030 ± 0.007	0.030 ± 0.009
Total CMPFa	0.31 ± 0.13	0.34 ± 0.15	0.43 ± 0.31	0.42 ± 0.31

Data are expressed as mean ± SD. SDMA, symmetric dimethylarginine; ADMA, asymmetric dimethylarginine; IS, indoxyl sulfate; HA, hippuric acid; pCS, p-cresylsulfate; IAA, indole acetic acid; CMPF, 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid.

^aOnly total concentration is given because the free concentration was below the detection limit.