I. What Is Estimated Glomerular Filtration Rate (eGFR) Testing?

One out of every three American adults is at risk of developing chronic kidney disease.

Why should you get tested?

Early diagnosis of kidney disease gives you a chance to get treated before your kidney function declines even further.

Who should get tested?

You should get tested if you have diabetes, heart disease, high blood pressure, or any other condition that increases your risk for chronic kidney disease. Those who have any symptoms of CKD should get tested as well.

When to get tested

Talk to your doctor about your symptoms or risk factors as soon as possible. Then have the test done as soon as your doctor orders it.

II. How to Prepare for Estimated Glomerular Filtration Rate (eGFR) Testing

Before the eGFR test, your doctor may ask you to temporarily stop taking antibiotics and other medications that can affect the results. Because your eGFR calculation is based on your creatinine level, your doctor may have ordered a basic metabolic panel or comprehensive metabolic panel. In this case, you may be required to fast overnight to ensure the most accurate results from the BMP or CMP.

III. How an Estimated Glomerular Filtration Rate (eGFR) Test Works

eGFR calculations are made based on your age, sex, race, and creatinine level. To have your creatinine level checked, you’ll need to give a blood sample, which you can do at your doctor’s office or at a testing facility. You can expect the technician to tie a tourniquet around your upper arm to make it easier to see your veins. After choosing a draw site, the technician will clean your skin to prevent infection, insert the needle into the vein, and collect a blood sample. The sample is then used to determine your creatinine level, and then laboratory personnel uses a mathematical formula to estimate your glomerular filtration rate (GFR) based on the results. If you had a basic or comprehensive metabolic panel, lab personnel would measure the amount of glucose, blood urea nitrogen (BUN), and several other substances in your blood as well.

IV. Understanding Estimated Glomerular Filtration Rate (eGFR) Testing Results

The eGFR test takes a short time to complete, but it may take a few days for your doctor to contact you with the results. Your eGFR is an estimate of how much blood passes through the filtering units of your kidneys every minute. A normal GFR level typically ranges from 90 to 120 milliliters per minute — your GFR may be a little lower if you’re an older adult. If your GFR is lower than 60 milliliters per minute for three months or more, you may have chronic kidney disease. Your doctor will let you know if you need additional tests to check your kidney function, such as a urinalysis or a creatinine urine test. Several factors, including sex and race, influence the results of the eGFR test, so just because your GFR is lower than normal doesn’t automatically mean you have kidney damage. It’s important to discuss the result with your doctor to find out what it means for your health.

V. Learn From Our Estimated Glomerular Filtration Rate (eGFR) Sources