Table 4.

Residual clearances relative to dialytic clearances and their effect on plasma solute concentrations

Solute	Twice Weekly			APC		APC2×/APC3×	TAC		TAC2×/TAC3×
	Kd,solute/Kd,urea	Kr,solute/Kr,urea	Fraction of Solute Removed by Residual Clearance	Twice Weekly, mg/dl	Thrice Weekly, mg/dl		Twice Weekly, mg/dl	Thrice Weekly, mg/dl
Urea	—	—	0.27±0.11	71±19	53±24	1.3	50±13	36±16	1.4
HIPP	0.52±0.11	8.0±7.2a	0.75±0.18b	3.1±3.1	6.3±3.0c	0.50	2.4±2.1	4.1±2.0	0.58
PAG	0.67±0.07	4.5±3.4a	0.63±0.19b	2.6±2.6	4.9±3.3c	0.53	1.8±1.6	3.0±2.1	0.60
IS	0.12±0.03	0.67±0.47a	0.56±0.24b	2.1±1.1	2.6±0.9	0.80	1.7±0.8	2.2±0.9	0.78
PCS	0.09±0.03	0.28±0.16a	0.44±0.22	4.6±2.3	5.0±2.2	0.92	3.9±1.9	4.2±1.8	0.91

Results are mean±SD. In the twice weekly group, the residual and dialytic clearances and the fraction removed by residual clearance could not be calculated for PAG in one patient and for HIPP in one patient because their post-treatment plasma concentrations fell below the assay range. APC values could therefore not be estimated in these patients. —, no data; APC, average pretreatment concentration; K_d,solute/K_d,urea, ratio of the dialytic solute clearance to dialytic urea clearance; K_r,solute/K_r,urea, ratio of the residual solute clearance to residual urea clearance; APC_2×/APC_3×, ratio of the APC in the twice weekly compared with the thrice weekly group; TAC_2×/TAC_3×, the ratio of TAC in twice weekly to thrice weekly patients; HIPP, hippurate; PAG, phenylacetylglutamine; IS, indoxyl sulfate; PCS, p-cresol sulfate.

^aP<0.05, K_d,solute/K_d,urea versus K_r,solute/K_r,urea.

^bP<0.05, values for the secreted solutes compared with urea.

^cP<0.05, twice versus thrice weekly.