eGFR Calculator (CKD-EPI 2021 Creatinine Equation)
Estimated glomerular filtration rate from serum creatinine, age and sex by the 2021 race-free CKD-EPI equation, with its KDIGO category.
Results
What this tool does
The CKD-EPI 2021 equation replaced the 2009 version after the American kidney societies recommended dropping the race coefficient; it is the creatinine-based eGFR most laboratories now report. It is normalised to a standard body surface of 1.73 m², unlike Cockcroft–Gault, so it suits staging of kidney disease more than drug dosing for people far from average size. A single value says little: kidney disease is defined by a low eGFR lasting at least three months, usually together with a urine test. Creatinine also rises after a lot of cooked meat, creatine supplements and in very muscular people, which can make the result look worse than it is.
Formula
eGFR = 142 × min(Scr ÷ κ, 1)^α × max(Scr ÷ κ, 1)^−1.200 × 0.9938^age × 1.012 [women] (κ = 0.7 women, 0.9 men; α = −0.241 women, −0.302 men)
Variables
| Symbol | Meaning | Unit |
|---|---|---|
ag | Age | a |
sc | Serum creatinine | — |
u | Unit of the creatinine value | — |
sx | Sex | — |
EG | eGFR (CKD-EPI 2021) | mL/min/1.73 m² |
CAT | GFR category (KDIGO) | — |
MG | Creatinine in mg/dL | mg/dL |
Worked example
- Age50 a
- Serum creatinine1
- Unit of the creatinine value1
- Sex1
- eGFR (CKD-EPI 2021)92 mL/min/1.73 m²
- GFR category (KDIGO)G1 — 90 or above (normal or high)
- Creatinine in mg/dL1.00 mg/dL
Limitations
- This tool is informational only. It does not diagnose, treat or replace a qualified health professional. Speak to a doctor before making decisions about your health.
- For work that must comply with a standard or be signed off, check the result against the applicable code and have it reviewed by a qualified engineer.