eGFR (CKD-EPI 2021)

Q: Why does CKD-EPI 2021 have no race factor?

The 2009 equation multiplied eGFR by 1.159 for Black patients. Because race is a social rather than biological category and the coefficient could delay diagnosis and referral, the NKF-ASN Task Force recommended the refitted 2021 equation without race; KDIGO 2024 advises against using race in eGFR.

Q: CKD-EPI 2021 vs 2009 — how different are the results?

For non-Black patients the 2021 equation gives slightly higher values (a few mL/min/1.73 m² on average), so a small number of patients move up a G category. Compare trends only with the same equation.

Q: eGFR or Cockcroft-Gault for drug dosing?

KDIGO 2024 considers validated eGFR equations appropriate for most dosing decisions. Some product labels, notably the DOACs, were developed with Cockcroft-Gault creatinine clearance, and the EHRA practical guide uses Cockcroft-Gault for DOAC dosing.

Q: How do I enter creatinine in µmol/L?

Divide by 88.4 to get mg/dL — for example 80 µmol/L ÷ 88.4 ≈ 0.90 mg/dL.

Estimated glomerular filtration rate, race-free equation

KDIGO 2024 GFR categories
NKF-ASN Task Force 2021

Sources last checked: 2026-10-13

eGFR (CKD-EPI 2021)

Estimated glomerular filtration rate, race-free equation

Serum creatinine (mg/dL)µmol/L ÷ 88.4 = mg/dLAge (years)

Sex

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Not valid in acute kidney injury, pregnancy, or extremes of muscle mass. For drug dosing, some sources still ask for Cockcroft-Gault.

Source: Inker LA et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med 2021;385:1737-1749.Open

Interpretation

G5 — kidney failure	< 15 mL/min/1.73 m² (KDIGO G5).
G4 — severe reduction	15–29 mL/min/1.73 m².
G3b — moderate–severe reduction	30–44 mL/min/1.73 m².
G3a — mild–moderate reduction	45–59 mL/min/1.73 m².
G2 — mild reduction	60–89 mL/min/1.73 m². A CKD diagnosis needs an additional marker of kidney damage.
G1 — normal or high	≥ 90 mL/min/1.73 m².

What is the eGFR (CKD-EPI 2021)?

The CKD-EPI 2021 creatinine equation estimates glomerular filtration rate (eGFR) from serum creatinine, age and sex, without the race coefficient of the 2009 version. Inker and colleagues refitted it on pooled North American cohorts with measured GFR and published it in 2021. The result is indexed to 1.73 m² body surface area and is classified into KDIGO GFR categories G1–G5.

When to use it

Staging chronic kidney disease (KDIGO G categories), together with albuminuria (A categories).
Screening and monitoring kidney function in hypertension, diabetes and cardiovascular disease.
As a default estimate for drug dosing where the product information accepts eGFR.

When not to use it

Acute kidney injury or rapidly changing creatinine — the equation assumes steady state.
Extremes of muscle mass (amputation, cachexia, bodybuilders), pregnancy, or children — use cystatin C or measured GFR, or a paediatric equation.
When a narrow-therapeutic-range drug label specifies Cockcroft-Gault creatinine clearance.

How it is calculated

eGFR = 142 × min(SCr/κ, 1)^α × max(SCr/κ, 1)^−1.200 × 0.9938^age × 1.012 [if female] κ = 0.7 (female) / 0.9 (male); α = −0.241 (female) / −0.302 (male) SCr in mg/dL (µmol/L ÷ 88.4); result in mL/min/1.73 m²

Clinical pearls and limitations

Not valid in acute kidney injury, pregnancy, or extremes of muscle mass. For drug dosing, some sources still ask for Cockcroft-Gault.
SI units: creatinine in µmol/L ÷ 88.4 = mg/dL (e.g. 100 µmol/L ≈ 1.13 mg/dL).
Many European laboratories still report CKD-EPI 2009 or the EKFC equation; KDIGO 2024 advises using the same equation consistently within a region and avoiding race in eGFR.
For drug dosing in very small or very large patients, de-index the result: eGFR × BSA / 1.73.
eGFR 60–89 alone is not CKD: G1 and G2 require another marker of kidney damage (albuminuria, structural or histological changes) for ≥ 3 months.
Where accuracy matters (e.g. borderline G3a/G3b, sarcopenia), the combined creatinine–cystatin C equation is more accurate.

Frequently asked questions

Why does CKD-EPI 2021 have no race factor?

The 2009 equation multiplied eGFR by 1.159 for Black patients. Because race is a social rather than biological category and the coefficient could delay diagnosis and referral, the NKF-ASN Task Force recommended the refitted 2021 equation without race; KDIGO 2024 advises against using race in eGFR.

CKD-EPI 2021 vs 2009 — how different are the results?

For non-Black patients the 2021 equation gives slightly higher values (a few mL/min/1.73 m² on average), so a small number of patients move up a G category. Compare trends only with the same equation.

eGFR or Cockcroft-Gault for drug dosing?

KDIGO 2024 considers validated eGFR equations appropriate for most dosing decisions. Some product labels, notably the DOACs, were developed with Cockcroft-Gault creatinine clearance, and the EHRA practical guide uses Cockcroft-Gault for DOAC dosing.

How do I enter creatinine in µmol/L?

Divide by 88.4 to get mg/dL — for example 80 µmol/L ÷ 88.4 ≈ 0.90 mg/dL.

Evidence and guidelines

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