Table 1. GFR-estimating equations based on serum creatinine, serum cystatin C, or both.

Biomarker	Equation	Clinical Performance
Abbreviated MDRD(50)	eGFR = 186 × SCr − 1.154 × age − 0.203 × 0.742 if female × 1.212 if black	Reliable at GFR levels <60 mL/min/1.73 m2 Tends to underestimate actual GFR at GFR levels ≥60 mL/min/1.73 m2 Limited validation in HIV-infected individuals in single, small study
Re-expressed MDRD(51)	eGFR = 175 × standardized SCr − 1.154 × age − 0.203 × 0.742 if female × 1.212 if black	Abbreviated and re-expressed MDRD equations used for non-enzymatic and standardized serum creatinine, respectively.
Cockcroft-Gault(48)	CrCl = ([140 ‒ age] × weight)/(72 × SCr) × 0.85 if female	Reliable at GFR levels <60 mL/min/1.73 m2 Tends to overestimate actual GFR at GFR levels ≥60 mL/min/1.73 m2 Limited validation in HIV-infected individuals in single, small study
CKD-EPI(56)	eGFR = 141 × min(SCr/κ, 1)α × max(SCr/κ, 1) ‒ 1.209 × 0.933 age × 1.018 if female × 1.159 if black where κ is 0.7 for males and 0.9 for females; α is −0.411 for males and −0.329 for females; min indicates minimum of SCr/κ or 1; and max indicates maximum of SCr/κ or 1.	Similar reliability as MDRD equation at GFR levels <60 mL/min/1.73 m2 More accurate than MDRD equation especially at GFR levels ≥60 mL/min/1.73 m2 Tends to overestimate actual GFR levels ≥60 mL/min/1.73 m2 but to a much lesser degree than the MDRD equation Has not been evaluated in HIV-infected population
Cystatin C only(73)	eGFR = 127.7 × CysC − 1.17 × age − 0.13 × 0.91 if female × 1.06 if black	Reliable for GFR <60 mL/min/1.73 m2 Slightly overestimates actual GFR at GFR ≥60 mL/min/1.73 m2 Has not been evaluated in HIV-infected population
Serum creatinine and cystatin C(73)	eGFR = 177.6 × SCr − 0.65 × CysC − 0.57 × age − 0.20 × 0.82 if female × 1.11 if black	Most accurate of the three cystatin C-based formulas developed by CKD-Epi group with 89% of eGFRs within 30% of measured GFRs Slightly overestimates actual GFR at GFR ≥60 mL/min/1.73 m2 Has not been evaluated in HIV-infected population

Abbreviations: eGFR, estimated glomerular filtration rate; SCr, serum creatinine; CrCl, estimated creatinine clearance; CysC, serum cystatin C. Units: SCr in mg/dL, CysC in mg/L, age in years, weight in kg.