eGFR is the estimated glomerular filtration rate, a calculated figure rather than a measured one, derived from serum creatinine together with age and sex. It expresses roughly how much blood the kidneys filter per minute, standardised to an average body surface area. It is the standard summary of overall kidney function and the basis for staging chronic kidney disease.
No readings for this marker yet.
A lowered eGFR most often reflects reduced filtration, whether temporary, as in dehydration or an acute illness, or sustained, as in chronic kidney disease; drugs that stress the kidneys can lower it as well. Values are also lower with age, since filtration declines gradually over a lifetime. Unusually high figures carry little meaning on their own and can occur with low muscle mass. A reduced result is confirmed by repeating the test over months before anything is concluded, and the interpretation belongs to a doctor.
Because the equation rests on creatinine, anything that shifts creatinine shifts eGFR, including muscle mass, limb amputation, a meat meal, creatine supplements, and pregnancy, and the estimate is unreliable when kidney function is changing quickly. It is read alongside creatinine itself, urea, and cystatin C, the latter giving an estimate that does not depend on muscle, together with urine albumin where available.
Reference ranges are general adult values and depend on lab, assay, age and sex. For orientation, not diagnosis — discuss results with your doctor.