The glomerular filtration rate (GFR) is a measure of how well your kidneys filter blood by removing waste and extra water to make urine. The GFR test measures how much blood your kidneys filter each minute, and it is recommended for people with chronic kidney disease or those who may develop kidney disease due to diabetes, high blood pressure, or heart disease. The standard way to estimate GFR is with a simple blood test that measures creatinine levels in the blood. Creatinine is a waste product that comes from the digestion of dietary protein and the normal breakdown of muscle tissue. An estimated GFR is called an eGFR, and it is calculated using a formula because measured GFR (mGFR) is a complicated and lengthy process. A reliable estimate of GFR is important for identifying chronic kidney disease (CKD) as early as possible because often, CKD does not have any symptoms until the later stages of the disease.

Here are some key points about GFR in blood tests:

• A GFR of 60 or higher is in the normal range.
• A GFR below 60 may mean kidney disease.
• A GFR of 15 or lower may mean kidney failure.

In addition to GFR, a urine test can also check for albumin in the urine, which is a sign of kidney damage. If you are diagnosed with kidney disease, your healthcare provider will explain what you can do to protect your kidneys from more damage and help prevent kidney failure.