Table 2.

Candidate solutes are presented according to the association of their kidney clearance with furosemide clearance (−log10[P]), separated by protein binding (>50% or ≤50%)

Protein Binding	−log(P): Furosemide	RMSE	−log(P) iGFR	Compound	Protein Binding (%)	CoV	CLr-to-CrCl Ratio
>50%	6.7	36.0	8.2	Androstan-3-ol-17-one 3-glucuronide	95	0.2	3.8
	6.3	36.6	4.2	Gentisic acid	64	0.4	2.3
	6.2	36.9	6.5	4-Pyridoxic acid	73	0.5	5.8
	6.1	37.2	2.4	o-Hydroxyhippuric acid	72	1.8	5.7
	6.1	37.0	5.8	Kynurenic acid	89	0.2	3.9
	5.1	38.8	5.7	4-Hydroxyphenylacetic acid	50	0.2	1.3
	4.2	40.4	4.3	2-Hydroxyphenylacetic acid	54	0.3	1.2
≤50%	7.9	33.8	4.6	L-Homocitrulline	11	0.3	3.0
	7.5	34.7	5.6	2-[(4-Aminobenzoyl)amino]acetic acid	19	0.3	10.9
	7.2	35.2	5.7	(2R)-3-Hydroxyisovaleroylcarnitine	21	0.1	3.0
	7.1	35.4	5.0	3′-Sialyllactose	21	0.3	5.7
	6.9	35.7	7.6	1-Methylxanthine	33	0.4	5.8
	6.8	35.8	7.4	N2,N2-Dimethylguanosine	29	0.2	5.3
	6.7	35.8	7.5	Guanidinosuccinic acid	5	0.2	6.6
	6.6	36.1	5.7	Galactonic acid	16	0.5	0.8
	6.6	36.2	8	Phenylacetyl-L-glutamine	22	0.3	7
	6.6	36.2	8.7	N2-[2-(1H-Indol-3-yl)acetyl]-L-glutamine	34	0.3	10.8
	6.6	36.2	7	3-Dehydrocarnitine	11	0.1	11.3
	6.4	36.4	5.2	1,4-Cyclohexanedicarboxylic acid	15	0.3	2.4
	6.3	35.8	7.9	Proline-hydroxyproline	14	0.3	3.2
	6.1	37.1	4.5	Inosine	18	0.4	1
	6.1	37.1	6.8	Xanthosine	18	0.2	4.7
	6	36.7	1.5	7-Methyluric acid	34	0.9	5.8
	6	37.2	7.3	6′-Sialyl-N-acetyllactosamine	17	0.2	4.6
	6	37.3	6.6	N-Methylglutamic acida	3	0.3	2.5
	5.7	37.7	7.6	N,N-Dimethylargininea	8	0.2	3.1
	5.7	37.7	5.4	7-Methylguanine	1	0.3	45.9

Only the top 20 solutes reaching statistical significance by Bonferroni (0.05/528) are presented. RMSE, root mean squared error from the −log(P): furosemide models; iGFR, iohexol GFR; CoV, coefficient of variation; CLr-to-CrCl ratio, solute clearance-to-creatinine clearance ratio.

^aDid not also reach significance for penciclovir clearance.