Creatinine Clearance (CrCl) Calculator 2025: Complete Guide to Kidney Function
Creatinine Clearance (CrCl) and estimated Glomerular Filtration Rate (eGFR) are the cornerstone of assessing kidney function. They guide drug dosing, CKD staging, and renal replacement therapy. Our CrCl Calculator supports Cockcroft-Gault, MDRD, and CKD-EPI formulas with unit conversion and race adjustment. This guide covers formulas, interpretation, limitations, and clinical use.
What is Creatinine Clearance?
CrCl estimates how well kidneys filter creatinine — a waste product from muscle. It’s measured in mL/min. Normal: >90 mL/min.
Formulas Explained
CrCl = [(140 − age) × weight(kg) × (0.85 if female)] / (72 × SCr(mg/dL))
eGFR = 175 × (SCr)^−1.154 × (age)^−0.203 × (0.742 if female) × (1.212 if Black)
Uses age, sex, SCr with different coefficients based on level
Which Formula to Use?
- Cockcroft-Gault: Drug dosing (FDA standard)
- MDRD: CKD staging (legacy)
- CKD-EPI: Most accurate eGFR (current guideline)
CKD Staging (KDIGO)
| Stage | eGFR (mL/min/1.73m²) | Description |
|---|---|---|
| 1 | ≥90 | Normal |
| 2 | 60–89 | Mild |
| 3a | 45–59 | Moderate |
| 3b | 30–44 | Moderate-Severe |
| 4 | 15–29 | Severe |
| 5 | <15 | Kidney Failure |
Drug Dosing Adjustments
- CrCl <30: Reduce dose of renally cleared drugs (e.g., metformin, digoxin)
- CrCl <10: Avoid nephrotoxic agents
- Use Drug Dosage Calculator after CrCl
Limitations
- Not accurate in acute kidney injury (AKI)
- Overestimates in obesity, underestimates in low muscle mass
- Cockcroft-Gault uses actual weight → adjust in extremes
Ideal Body Weight (IBW) Adjustment
For obese patients, use IBW in Cockcroft-Gault:
IBW (male) = 50 + 0.91 × (height(cm) − 152.4)
IBW (female) = 45.5 + 0.91 × (height(cm) − 152.4)
Advanced Tips
- Trend eGFR over time, not single value
- Pair with Hydration Status
- Use cystatin C for confirmation in borderline cases
FAQs
Is CrCl the same as eGFR? No. CrCl = mL/min; eGFR = mL/min/1.73m² (normalized to body surface).
Can I use CrCl in children? No. Use Schwartz formula.
Why race in MDRD? Historical. CKD-EPI 2021 is race-free.
Conclusion
Accurate CrCl/eGFR estimation is critical for safe medication use and CKD management. Use our 2025 Creatinine Clearance Calculator to guide therapy. Always interpret with clinical context and repeat testing. Ready to assess kidney function? Calculate now!
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