Blood test: eGFR (estimated glomerular filtration rate)
Learn about eGFR (estimated glomerular filtration rate), what it means and what you should do based on your result.
- Medically reviewed by
- AKF's Medical Advisory Committee
- Last updated
- October 20, 2022
What is eGFR?
eGFR (estimated glomerular filtration rate) is a measure of how well your kidneys are working. Your eGFR is an estimated number based on a blood test and your age, sex, body type and race.
eGFR is considered a mostly reliable test for doctors to know how well your kidneys are working. However, the eGFR may not be accurate if you are younger than 18, pregnant, very overweight or very muscular. In addition, other tests such as an ultrasound or a kidney biopsy may be ordered to find a cause of your kidney disease.
Please note: eGFR is an estimate of how well your kidneys are working. The way eGFR is calculated will be changing. Currently the test considers your age, sex and race, among other things. A task force led by the National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) is working on recommendations that may remove Black race as a factor in the eGFR calculation. The task force has been seeking the input of kidney disease experts to come up with the best way to make the eGFR test as accurate as possible. American Kidney Fund (AKF) advised the task force to remove race from the eGFR so there is no bias in testing kidney function. This would help to make sure that every person will receive health care that is fair and of the highest quality. When the NKF-ASN task force makes its recommendations, AKF will promptly review them and then update our educational materials.
How do I find out my eGFR?
You will have a blood test to see how much creatinine is in your blood. Creatinine is a waste product in your blood that comes from your muscles. Healthy kidneys take creatinine out of your blood and send it out of your body through your urine. If your kidneys are not working the way they should, creatinine will build up in your blood.
The eGFR test report will give a number that will tell doctors the amount of creatinine in your blood. You will also get a lab report that will contain this number. Be sure to talk to your doctor about what your results mean for you.
Can my eGFR change?
Your eGFR can change over time and can change based on some other problems, like if you have not been drinking enough water.
As chronic kidney disease gets worse, your eGFR number will go down. If caught early, healthy life changes like following a kidney-friendly eating plan and getting enough exercise may help slow down the progression of CKD and how fast your eGFR changes.
Can I have kidney disease even if my eGFR is normal?
Yes, your eGFR may still be in the normal range even if you have some signs of kidney damage, such as protein in your urine (pee) or physical damage to your kidneys.
If you have protein in your urine, your doctor will check you again to make sure it is not caused by something else, like being dehydrated.
Do I need to do anything to prepare for my eGFR test?
Your doctor may have you fast (not eat or drink) or avoid certain foods for several hours before the test. They will let you know how to prepare.
You may have a blood creatinine test as part of a regular check-up or if your doctor thinks you might have kidney disease. Your doctor will figure out your eGFR using your creatinine blood test result and your age, sex, weight and race.
What does my eGFR mean?
A normal eGFR is 60 or more. If your eGFR is less than 60 for three months or more, your kidneys may not be working well. Use this chart to see what your eGFR may mean.
eGFR | 90 or higher (normal range) | 60-89 (normal range) | 45-59 | 30-44 | 15-29 | Less than 15 |
|---|---|---|---|---|---|---|
| Kidney function | Normal kidney function Some signs of kidney damage, such as protein in urine (i.e., pee) or physical damage to the kidneys | Mild loss of kidney function Signs of kidney damage, such as protein in urine or physical damage to the kidneys | Moderate kidney function Sometimes, symptoms of kidney damage, such as:
| Moderate kidney function Some symptoms of kidney damage, such as:
| Severe kidney damage Symptoms of kidney damage and other health problems, such as:
| Kidneys are close to failure or have already failed People at this stage feel very sick and need dialysis or a kidney transplant to stay alive |
| Stage of kidney disease | Stage 1 | Stage 2 | Stage 3a | Stage 3b | Stage 4 | Stage 5 |
| What happens next? | Talk to your doctor about ways you can slow down the damage to your kidneys. | Talk to your doctor about ways you can slow down the damage to your kidneys. | If your eGFR was 60 or less, talk to your doctor right away! Ask when you should be tested again. If this was your first eGFR test, you may need to be tested again in a few months. Your doctor will want to see if your eGFR is 60 or less for three months or more. | If your eGFR was 60 or less, talk to your doctor right away! Ask when you should be tested again. If this was your first eGFR test, you may need to be tested again in a few months. Your doctor will want to see if your eGFR is 60 or less for three months or more. | If your eGFR was 60 or less, talk to your doctor right away! Ask when you should be tested again. If this was your first eGFR test, you may need to be tested again in a few months. Your doctor will want to see if your eGFR is 60 or less for three months or more. | If your eGFR was 60 or less, talk to your doctor right away! Ask when you should be tested again. If this was your first eGFR test, you may need to be tested again in a few months. Your doctor will want to see if your eGFR is 60 or less for three months or more. |
No matter what your eGFR is, take these steps to keep your kidneys as healthy as possible:
- Keep a healthy blood pressure (less than 120/80 for most people).
- Control your blood sugar if you have diabetes.
- Follow a healthy low-salt, low-saturated-fat eating plan.
- Do something active for at least 30 minutes most days of the week, such as walking or biking.
- Keep a weight your doctor says is healthy for you.
- Do not smoke or use tobacco.
- Ask your doctor about medicines that may help protect your kidneys.
No matter what your eGFR is, ask your doctor when you should be tested again and what other tests you should have. Your doctor may want to do other tests to look for signs of kidney problems, such as:
- Urine test for protein or blood
- Blood test for other wastes
- Blood pressure
- Blood sugar (glucose) test
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