CKD-EPI = Chronic Kidney Disease Epidemiology Collaboration.

The CKD-EPI cystatin C equation, expressed as a single equation, is:
GFR = 133 x min(SCysC/0.8, 1)^-0.499 x max(SCysC/0.8, 1)^-1.328 x 0.996^Age x 0.932 [if female], where SCysC is serum cystatin C (mg/L), min indicates the minimum of SCysC/0.8 or 1, and max indicates the maximum of SCysC/0.8 or 1.

Cystatin C inversely correlates with the glomerular filtration rate (GFR), that is, elevated levels of cystatin C indicate decreased GFR. Cystatin C may provide more accurate assessment of GFR for very obese, elderly, or malnourished patients than creatinine. Cystatin C equation does not require patient ethnic data, and can be used for those patients with this information unavailable.

See also , MDRD equation with 6 inputs () and MDRD equation with 4 inputs ().

Normal GFR in mL/min/1.73 m2 of body surface area.
See .