CKD-EPI 2021: eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^-1.200 × 0.9938^Age × (1.012 if female)
κ = 0.7 (F), 0.9 (M) | α = -0.241 (F), -0.302 (M)
Kidney Function Calculator 2025: eGFR, CKD Staging, and Clinical Use
eGFR estimates glomerular filtration rate from serum creatinine, age, and sex. Our calculator uses CKD-EPI 2021 — race-free, validated across populations. Essential for CKD diagnosis, drug dosing, and AKI monitoring.
Formula Comparison
| Formula | Use Case | Limitations |
|---|---|---|
| CKD-EPI 2021 | General, staging, most accurate | ≥18 years |
| MDRD | Older studies, drug labeling | Underestimates high GFR |
| Cockcroft-Gault | Drug dosing (CrCl) | Uses weight, outdated |
CKD Stages (KDIGO)
- G1: ≥90 mL/min (normal)
- G2: 60–89 (mild)
- G3a: 45–59 (mild-moderate)
- G3b: 30–44 (moderate-severe)
- G4: 15–29 (severe)
- G5: <15 or dialysis
Interpretation Guide
- eGFR >90: Normal (check albuminuria)
- 60–90: Monitor annually if risk factors
- <60: CKD confirmed (repeat in 3 months)
- <30: Nephrology referral
Special Cases
- AKI: ≥0.3 mg/dL rise in 48h or ≥50% in 7d
- Transplant: Use CKD-EPI
- Amputation: Adjust weight in Cockcroft-Gault
Drug Dosing
- Use Cockcroft-Gault for renally cleared drugs (e.g., digoxin, vancomycin)
- Round eGFR to 10, 30, 50, etc. for guidelines
Limitations
- Not for <18 years (use Schwartz)
- Inaccurate in acute changes, pregnancy, extremes of muscle mass
- Cystatin C improves accuracy in borderline cases
Pro Tips
- Repeat eGFR in 1–3 months for confirmation
- Check UACR (urine albumin-to-creatinine ratio)
- Avoid NSAIDs, dehydration before testing
FAQs
Why no race in CKD-EPI 2021? Race is social, not biological. Improves equity.
Can I use this in children? No — use pediatric formulas.
What if creatinine is in µmol/L? Convert: mg/dL = µmol/L ÷ 88.4
Conclusion
Use our 2025 Kidney Function Calculator with CKD-EPI for accurate staging and management. Always interpret with clinical context.
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