Table 1.

Baseline reference values of novel biomarkers of acute kidney injury obtained from different studies

Biomarker	Injury	Source	Test	Unit	Healthy controls (range)
Cystatin C	Proximal tubule injury	Serum	Nephelometric immunoassay/ELISA	mg/L	0.53-0.95[38]
					0. 85 ± 0.21[39]
		Urine	Nephelometric immunoassay/ELISA	mg/L	0.051-0.28[37]
					0.02-0.11[96]
NGAL	Ischemia and nephrotoxins	Serum	ELISA	ng/mL	86.3 ± 43.0 (men)[54]
					88.9 ± 38.2 (women)[54]
					56.71 ± 17.57[39]
					1.7 ± 0.5[55]
					0.4-100[56]
		Urine	ELISA	ng/mL	5.7-17.7[55]
					11.94 ± 8.09[39]
					0.8-28.9 (men)[96]
					1.9-316.7 (women)[96]
KIM-1	Ischemia and nephrotoxins	Urine	ELISA	pg/mL	59-2146[70]
					395.1 ± 398.8[39]
					31.0-1000.0[56]
					31.0-1736.5[96]
IL-18	Toxic, delayed graft function	Urine	ELISA	pg/mL	1.4-1.8[80]
					3.0-108.6[96]
					6.2-311.1[96]
L-FABP	Ischemia and nephrotoxins	Urine	ELISA	ng/mL	3-400[83]
				μg/gCr	5.67 (2.74-8.21)[87]
NAG	Tubule injury	Urine	Colorimetry	U/g	0.75-0.90 U/g[95]
					1.06 ± 0.1 U/g (children)[90]

¹Lower reference values are not presented due to the detection limit of 0.05 mg/L. NGAL: Neutrophil gelatinase-associated lipocalin; KIM-1: Kidney injury molecule-1; IL-18: Interleukin-18; L-FABP: Liver-type fatty acid binding protein; NAG: N-acetyl-β-D-glucosaminidase; ELISA: Enzyme-linked immunosorbent assay; U: Unit.