Stages and labs

What Is eGFR? Understanding Your Kidney Function Number

Last reviewed October 28, 2026 · General information, not medical advice

This article is general information. Your nephrologist or renal dietitian knows your lab results and can tell you what is right for you.

If you have had a kidney check, you have probably seen the abbreviation eGFR on your lab report. It stands for estimated glomerular filtration rate, and it is the number doctors rely on most to judge kidney function. This article explains what it is and what it is not. It cannot interpret your own result.

What eGFR measures

Your kidneys filter waste and extra water out of the blood. The glomerular filtration rate (GFR) is the measure of how well they do this. The National Kidney Foundation (NKF) explains that eGFR is a calculated estimate of the GFR, and that the standard way to estimate it is with a simple blood test that measures creatinine. MedlinePlus, the National Library of Medicine’s health site, says the estimate is calculated from the creatinine level together with age, weight, height and sex. Cystatin C, another blood marker, can also be used.

What creatinine is

Creatinine is a waste product from the breakdown of muscle and from digesting dietary protein. Healthy kidneys remove it from the blood, and the level rises as kidney function falls. The NKF notes that diet, muscle size, malnutrition and other long-term conditions can also affect creatinine levels, which is one reason the result is an estimate.

What the ranges mean

The NKF gives these general ranges:

90 or higher: normal range.
60 to 89: may mean early-stage kidney disease.
15 to 59: may mean kidney disease.
Below 15: may mean kidney failure.

These ranges line up with the stages of CKD, which are described in CKD Stages 1 to 5 Explained. NIDDK adds that GFR cannot be raised, but that a decline can be slowed.

eGFR goes down with age

The NKF points out that eGFR naturally declines with age, even without kidney disease, and lists average values by age group: 116 at ages 20 to 29, 107 at 30 to 39, 99 at 40 to 49, 93 at 50 to 59, 85 at 60 to 69 and 75 at 70 and older. Your doctor looks at your result in context, not just against one number.

Limits of the number

The NKF and MedlinePlus both stress that eGFR is not a perfect test. A creatinine-based eGFR can be inaccurate, particularly in the early stages, and several things can affect it. The NKF lists pregnancy, age over 70, unusual muscle mass, cirrhosis, nephrotic syndrome, a past solid organ transplant and some medicines. MedlinePlus adds severe malnutrition, muscle-wasting conditions, advanced liver disease and limb amputation. A more precise test called measured GFR exists, but it is less widely available, takes longer and costs more.

One number is not the whole picture

Doctors usually pair eGFR with a urine test for albumin. Read more in Kidney Function Tests: eGFR, Creatinine and ACR Explained. If you want to talk through your own results, these questions can help you prepare.

Sources

We summarize these pages in our own words. Figures are quoted as the sources give them, with the dates shown, and official pages can be updated, so please check the originals.

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