Table 1. Spearman rank correlations between serum levels of uremic toxins in HD patients.

	T-IS	F-IS	T-PCS	F-PCS
T-IS	1.00	—	—	—
T-IG	0.67**	0.73***	0.33	0.47*
T-IAA	−0.54*	−0.21	0.15	0.09
T-PCS	0.32	0.62**	1.00	—
T-PCG	0.34	0.62**	0.79***	0.81***
T-PhS	0.53*	0.43	0.18	0.22
T-PhG	0.72*	0.30	−0.28	−0.38
T-PAA	0.13	0.46*	0.53*	0.56*
T-PAGln	0.42	0.78***	0.83***	0.92***
T-HA	0.22	0.41	0.41	0.44
T-4EtPhS	−0.05	0.06	0.35	0.29
T-CMPF	0.02	−0.15	−0.40	−0.36
F-IS	0.78***	1.00	—	—
F-IG	0.67**	0.72***	0.30	0.44
F-IAA	0.15	0.59**	0.63**	0.71***
F-PCS	0.39	0.76***	0.95***	1.00
F-PCG	0.35	0.66**	0.81***	0.85***
F-PhS	0.65**	0.73***	0.43	0.54*
F-PhG	0.38	0.52*	0.31	0.39
F-PAA	0.23	0.53*	0.59**	0.61**
F-PAGln	0.37	0.78***	0.87***	0.95***
F-HA	0.33	0.56*	0.49*	0.54*
F-4EtPhS	−0.04	0.27	0.62**	0.63**
F-CMPF	0.04	0.16	0.16	0.17

* p<0.05, ** p<0.01, *** p<0.001. T: total, F: free, total=protein-bound+free. IS: indoxyl sulfate, IG: indoxyl glucuronide, IAA: indoleacetic acid, PCS: p-cresyl sulfate, PCG: p-cresyl glucuronide, PhS: phenyl sulfate, PhG: phenyl glucuronide, PAA: phenylacetic acid, PAGln: phenylacetylglutamine, HA: hippuric acid, EtPhS: 4-ethylphenyl sulfate, CMPF: 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid.