. Author manuscript; available in PMC: 2017 Sep 1.

Published in final edited form as: Am J Transplant. 2016 Apr 22;16(9):2532–2544. doi: 10.1111/ajt.13765

TABLE 1.

COMMON METHODS FOR MEASURING GLOMERULAR FILTRATION RATES

MEASURE	FORMULA	CALCULATION
Estimated
Creatinine
	MDRD4	175 × (S_cr)^−1.154 × (Age)^−0.203 × (0.742 if female) × (1.212 if African American)
	MDRD6	198 × [S_cr (mg/dL)]^–0.858 × [age]^–0.1678 × [0.822 if patient is female] × [1.178 if patient is black] × [serum urea nitrogen concentration (mg/dL)]^–0.293 × [urine urea nitrogen excretion (g/d)] ^0.249
	2009 CKD-EPI Creatinine equation	141 × min (S_cr/κ, 1)^α × max(S_cr/κ, 1)^−1.209 × 0.993^Age × 1.018 [if female] × 1.159 [if black] where: S_cr is serum creatinine in mg/dL, κ is 0.7 for females and 0.9 for males, α is −0.329 for females and −0.411 for males, min indicates the minimum of S_cr/κ or 1, and max indicates the maximum of S_cr/κ or 1.
Cystatin C
	2012 CKD-EPI cystatin C equation	133×min(SCysC/0.8, 1)^−0.499 × max(SCysC/0.8, 1)^−1.328 × 0.996^Age [×0.932 if female] where: SCysC is serum cystatin C (in mg/l), min indicates the minimum of SCysC/0.8 or 1, and max indicates the maximum of SCysC/0.8 or 1.
	2012 CKD-EPI creatinine-cystatin C equation	135×min(SCr/κ, 1)^α ×max(SCr/κ, 1)^−0.601 ×min(SCysC/0.8, 1)^−0.375× max(SCysC/0.8, 1)^−0.711×0.995^Age [×0.969 if female] [×1.08 if black] where: SCr is serum creatinine (in mg/dl), SCysC is serum cystatin C (in mg/l), κ is 0.7 for females and 0.9 for males, α is −0.248 for females and −0.207 for males, min(SCr/k, 1) indicates the minimum of SCr/k or 1, and max(SCr/k, 1) indicates the maximum of SCr/k or 1; min(SCysC/0.8, 1) indicates the minimum of SCysC/0.8 or 1 and max(SCysC/0.8, 1) indicates the maximum of SCysC/0.8 or 1.
Radioisotope
Measured
Iothalamate		Iothalamate clearance (volume of plasma cleared of the marker per unit time): UV/P where: U = Urinary Concentration of the substance, V = Urine flow rate (urinary volume), P = Average plasma concentration)
Iohexol		Blood specimens are obtained after subcutaneous injection of non-radiolabeled iohexol and results are analyzed via liquid chromatography-tandem mass spectrometry

Scr: Serum Creatinine; SCys: Serum Cystatin C