Estimated Glomerular Filtration Rate

An eGFR result looks precise, but it is an estimate rather than a direct measurement of filtration. Its clinical meaning comes from four questions: Is the creatinine at steady state? Is the abnormality persistent? Is the value changing over time? What does the urine albumin-to-creatinine ratio show? Canadian laboratories report eGFR in mL/min/1.73 m². The race-free CKD-EPI 2021 equation is the adult equation supported by the Canadian Society of Nephrology and KDIGO, but provincial laboratories have adopted it on different timelines (Alberta Precision Laboratories switched from a modified 2009 equation on 20 January 2026), so check which equation the reporting laboratory uses. The value is indexed to a standard body surface area, so it is useful for comparing kidney function across patients but is not automatically the patient's absolute clearance for every drug decision. When body composition, illness, or a medication makes creatinine misleading, confirm the estimate before acting on a high-consequence threshold. At the bedside, a low eGFR is a signal to investigate rather than a diagnosis by itself. Pair it with the trend in creatinine, urine output, albuminuria,...