Understanding GFR

What is GFR?

Your glomerular filtration rate (GFR) is a measure of how well your kidneys are filtering wastes from your blood. Your GFR has been estimated from a routine measurement of creatinine in your blood.

Creatinine is a waste product formed by the normal breakdown of muscle cells. Healthy kidneys take creatinine out of the blood and put it into the urine to leave the body. When kidneys are not working well, creatinine builds up in the blood.

What does my GFR number mean?

As you get older, the average GFR number drops. However, a low GFR with a value below 60 suggests some kidney damage has occurred. This means that your kidneys are not working at full strength.

How important is my GFR number?

Your doctor will use your GFR number as one clue to how well your kidneys are working. Your doctor will also look at other factors, including
• protein (albumin) in your urine
• diabetes • high blood pressure

Depending on these factors, your doctor may decide that you have chronic kidney disease. If you have chronic kidney disease, controlling your diabetes or high blood pressure can help prevent more damage to your kidneys and other problems like heart attacks and strokes.

What do my kidneys do?

Healthy kidneys filter your blood. They remove waste and extra water, which become urine. The wastes in your blood come from the normal breakdown of active tissues and from food you eat. After your body has taken what it needs from the food, waste is sent to the blood. If your kidneys do not remove these wastes, the wastes build up in the blood and damage your body.

Where can I get more information?

For more information about kidney disease, contact the National Kidney Disease Education Program at 1-866-454-3639 or www.nkdep.nih.gov.

The National Kidney Disease Education Program is an initiative of the National Institutes of Health, U.S. Department of Health and Human Services. NIH Publication No. 04-5579 August 2004