Understanding Your eGFR

Estimated Glomerular Filtration Rate

eGFR is one of the most important “kidney numbers” you’ll ever see on lab work—it estimates how well your kidneys are filtering waste from your blood. (see the generated image above) At Kidney Konnect, we use eGFR education to help our community catch kidney disease earlier, ask better questions, and take practical steps to protect kidney function.

What eGFR means (in plain language)

Your kidneys filter your blood by removing waste and extra water to make urine. (see the generated image above) GFR (glomerular filtration rate) describes how well that filtering is happening, and eGFR is the estimated version calculated from a blood test rather than measured through a longer, more complex process. (see the generated image above)

CKD often has no symptoms until later stages, which is why reliable estimates of kidney filtration are so valuable—especially for early detection. (see the generated image above) The National Kidney Foundation also notes that millions of U.S. adults may have CKD and many are unaware, which is exactly why we push for routine testing when risk is present.

How eGFR is calculated (and what can affect it)

The standard eGFR test starts with a simple blood test that measures creatinine. Creatinine is a waste product that comes from digesting dietary protein and the normal breakdown of muscle. (see the generated image above)

Creatinine (and therefore eGFR) can be influenced by factors beyond CKD—such as diet, muscle size, malnutrition, and other chronic diseases—so it’s important to interpret your number in context. (see the generated image above) NKF also lists situations that can affect eGFR estimates, including pregnancy, being over age 70, unusual muscle mass, cirrhosis, nephrotic syndrome, having had a solid organ transplant, and some medications.

eGFR vs. “measured GFR” (mGFR)

Because a true measured GFR (mGFR) is a longer and more complex process, healthcare professionals typically use eGFR for routine care. (see the generated image above) NKF explains that mGFR can be more accurate (including in early-stage disease) but is not as widely available, takes more time, and is more expensive. (see the generated image above

Why eGFR testing is done

Your clinician may recommend eGFR testing if you’re at higher risk for CKD—especially if you have diabetes, high blood pressure, overweight/obesity, are over age 60, or have a family history of CKD or kidney failure. (see the generated image above) CKD is often not due to a single cause, but to a combination of physical, environmental, and social and/or economic factors, which is another reason Kidney Konnect advocates for earlier screening and support. (see the generated image above)

You may also need eGFR testing if you’re experiencing later-stage symptoms that can be linked to CKD, such as changes in urination, itching, fatigue, swelling in the arms/legs/feet, muscle cramps, nausea/vomiting, or loss of appetite.

Understanding your results (ranges)

In adults, an eGFR of 90 or higher is generally considered in the normal range. (see the generated image above) NKF lists these general result ranges: 60–89 may mean early-stage kidney disease; 15–59 may mean kidney disease; and below 15 may mean kidney failure. (see the generated image above)

eGFR also tends to decline with age even in people without kidney disease, and NKF provides average eGFR values by age group.

CKD stages (based on eGFR)

Healthcare professionals use eGFR (or mGFR) to help determine CKD stage. (see the generated image above) NKF outlines five stages tied to eGFR ranges—stage 1 (90+ with signs of kidney damage like protein in urine) through stage 5 (less than 15, kidney failure).

What to do next (Kidney Konnect guidance)

If you have CKD risk factors, ask your healthcare professional to order an eGFR lab test and pair it with a urine albumin test (uACR) so you have a more complete picture of kidney health. (see the generated image above) If eGFR is lower than expected, you may be advised to repeat testing (often in about 3 months) to confirm whether the change is persistent. (see the generated image above)

Depending on your stage and overall health, your clinician may recommend steps like reviewing medication doses for kidney safety, getting nutrition counseling, starting medications that may slow CKD progression (such as ACE inhibitors/ARBs, SGLT2 inhibitors, or nonsteroidal mineralocorticoid receptor antagonists), and/or beginning care with a kidney specialist (nephrologist).

Questions to ask at your next appointment

Use these questions to turn a lab result into a real plan:

What is my eGFR number, and what CKD stage does that put me in?
Can we test my urine for albumin (uACR) to get the full picture?
Should I repeat my eGFR in about 3 months to confirm the result?
Do any of my current medications need adjusting for kidney function?
Should I meet with a dietitian for kidney-supportive nutrition counseling?
Should I be on medications that may help slow CKD progression (ACE/ARB, SGLT2 inhibitor, nsMRA), if appropriate for me?
At what point should I start seeing a nephrologist?