Glomerular Filtration Rate (GFR)

What is GFR?

GFR - glomerular filtration rate is the best test to measure your level of kidney function and determine your stage of kidney disease. Your doctor can calculate it from the results of your blood creatinine test, your age, body size and gender. Your GFR tells your doctor your stage of kidney disease and helps the doctor plan your treatment. If your GFR number is low, your kidneys are not working as well as they should. The earlier kidney disease is detected, the better the chance of slowing or stopping its progression.

What are the Stages of Chronic Kidney Disease (CKD)?

Stage Description (GFR)
1 Kidney damage with normal kidney function 90 or above
2 Kidney damage with mild loss of kidney function 89 to 60
3a Mild to moderate loss of kidney function 59 to 44
3b Moderate to severe loss of kidney function 44 to 30
4 Severe loss of kidney function 29 to 15
5 Kidney failure Less than 15

Your GFR number tells you how much kidney function you have.
As kidney disease gets worse, the GFR number goes down.

What happens if my test results show I may have chronic kidney disease?

  • A GFR below 60 for three months or more or a GFR above 60 with kidney damage (marked by high levels of albumin in your urine) indicates chronic kidney disease. Your doctor will want to investigate the cause of your kidney disease and continue to check your kidney function to help plan your treatment.
  • Typically, a simple urine test will also be done to check for blood or albumin (a type of protein) in the urine. When you have albumin in your urine it is called albuminuria.  Blood or protein in the urine can be an early sign of kidney disease.
  • People with a high amount of albumin in their urine are at an increased risk of having chronic kidney disease progress to kidney failure. (See chart below)

Your doctor may also suggest further testing, if necessary, such as:

  • Imaging tests such as an ultrasound or CT scan to get a picture of your kidneys and urinary tract. This tells your doctor whether your kidneys are too large or too small, whether you have a problem like a kidney stone or tumor and whether there are any problems in the structure of your kidneys and urinary tract.
  • A kidney biopsy, which is done in some cases to check for a specific type of kidney disease, see how much kidney damage has occurred and help plan treatment. To do a biopsy, the doctor removes small pieces of kidney tissue and looks at them under a microscope.

Your doctor may also ask you to see a kidney specialist called a nephrologist who will consult on your case and help manage your care.

Glomerular Filtration Rate (GFR) Brochure

Calculate your Glomerular Filtration Rate (GFR)

If you would like more information, please contact us.

© 2015 National Kidney Foundation. All rights reserved. This material does not constitute medical advice. It is intended for informational purposes only. Please consult a physician for specific treatment recommendations.