Estimated glomerular filtration rate (eGFR) is a calculated measure of how efficiently the kidneys are filtering waste products from the blood each minute. It is derived from the creatinine level (and sometimes cystatin C) along with the patient's age and sex, using validated equations such as CKD-EPI.

A normal eGFR is greater than 60 mL/min/1.73m². Values below 60 that persist for more than 3 months indicate chronic kidney disease (CKD), and the eGFR value is used to stage CKD from G1 (normal) through G5 (kidney failure). eGFR is the primary tool used to diagnose, monitor, and guide the management of kidney disease and is reported automatically alongside creatinine on most blood test results.