eGFR and creatinine clearance (CrCl) both appear in kidney care, but they estimate different things and should not be treated as interchangeable numbers.
What is eGFR?
eGFR estimates glomerular filtration rate. Contemporary CKD-EPI equations are validated against measured GFR and are widely used for evaluating and following kidney filtration. Results are usually standardized to 1.73 m² of body surface area.
What is CrCl?
Creatinine clearance estimates how quickly creatinine is cleared. The Cockcroft–Gault equation uses age, weight, sex, and serum creatinine and reports an estimated CrCl in mL/min. Creatinine is filtered and also secreted by kidney tubules, so creatinine clearance is not identical to measured GFR.
Why is medication dosing more complicated?
Many older drug labels and studies used Cockcroft–Gault CrCl. More recent kidney and regulatory guidance increasingly supports modern race-free eGFR approaches, but the renal-function measure specified for dosing can still differ by drug and label. A patient should not switch between eGFR and CrCl or change a medicine dose without checking the specific prescribing information and a clinician or pharmacist.
Related calculators
- eGFR calculator — for understanding a contemporary filtration estimate
- CrCl calculator — for seeing a Cockcroft–Gault estimate
The Life Choice Note CrCl calculator does not recommend medication doses. Body size, older age, acute kidney changes, and unusual muscle mass can all complicate interpretation.
Four checks before comparing reports
- Copy the label and units together. Korean labels may include 추정 사구체여과율 (eGFR), 크레아티닌 청소율 (creatinine clearance), and 혈청 크레아티닌 (serum creatinine). Wording varies by laboratory. Keep the test date, number, inequality sign (such as >60), units, and equation name exactly as reported.
- mL/min/1.73 m² is not the same notation as mL/min. The first is indexed to a standard body surface area. Clinicians may convert eGFR to individual mL/min using body size; this does not turn it into Cockcroft–Gault CrCl. Matching units do not make the estimates identical.
- Check how CrCl was obtained. Was it measured using a timed urine collection or estimated with an equation? For Cockcroft–Gault, using actual, ideal, or adjusted body weight can produce different results. Ask the clinician or pharmacist which method and weight were used; do not choose a weight or equation to select a medicine dose.
- Bring the clinical context. Both eGFR and estimated CrCl may be less reliable during acute illness when creatinine is changing rapidly. Bring previous results with dates and mention recent acute illness. Changing units or calculators does not remove this limitation.
Suggested wording: “Which equation and units were used? If this is estimated CrCl, which body weight was used? Is my kidney function stable enough to interpret this estimate?”
These checks prepare a clinical discussion; they are not instructions to start, stop, or change a medicine. Sources: NIDDK dosing and body surface area, NKF estimates, weight, and stable-function FAQ, NIDDK creatinine-based estimate limitations. Sources for this addition checked 2026-11-01.
Questions to discuss
- Which kidney-function measure does this medicine’s prescribing information use?
- Is my result close to a dosing threshold?
- Could body size or muscle mass make a creatinine-based estimate less reliable?
Related guides
Lab result guide · Understanding creatinine and eGFR
For a medication review, bring actual product names and doses on the medication and supplement list. Do not change a dose using a number on this page.
Sources and review status
NIDDK: Determining drug dosing in adults with CKD · National Kidney Foundation: Cockcroft–Gault and transition to eGFR · FDA 2024 renal impairment guidance. Sources checked 2026-09-25. General information only; this page does not provide a personal medication dose. It has not been represented as independently physician-reviewed.