Answers

What is eGFR, and what is a normal result?

Two lab reports can print different eGFRs for reasons that have nothing to do with your kidneys, and "normal" sits at different lines on different pages. The equation, your age and the trend all change how one number reads.

Arun Verma, co-founder of Triangle · 2026-10-19

This is not clinical evidence and not medical advice. It does not replace your care team. Discuss anything here with your clinician before you act on it.

What is eGFR?

eGFR is an estimate of how well your kidneys filter your blood, worked out from a blood test. The letters stand for estimated glomerular filtration rate. Providers use the amount of creatinine in your blood, a waste product from the normal breakdown of muscle, to estimate it, NIDDK says. The estimate comes from an equation. The 2021 CKD-EPI creatinine equation uses creatinine, age and sex. Some labs also measure cystatin C, a protein many cells make, and MedlinePlus says the two are sometimes used together in adults. Measuring GFR directly is complicated and not widely available, so the estimate is what you usually see. Whatever the equation, an eGFR is an estimate, not a precise measure of kidney function.

What is a normal eGFR result?

Usually 90 or above, though sources draw the line in different places. NKF says the normal eGFR in adults is usually more than 90. KDIGO's top category, G1, is 90 or above, labeled "normal or high." NIDDK's patient page puts the line lower and calls a GFR of 60 or more the normal range. KDIGO's risk grid shades 60 to 89 as low risk and not CKD when there are no other markers of kidney disease. Age moves the number too. NIDDK's table of average eGFR by age, from a national survey, runs from 116 at ages 20 to 29 down to 75 at 70 and older. KDIGO reports eGFR in ml/min per 1.73 m². MedlinePlus notes that normal ranges may vary slightly among laboratories.

When does a low eGFR count as chronic kidney disease?

When it stays below 60 for at least 3 months. KDIGO's criteria for CKD list a GFR below 60 ml/min per 1.73 m² (categories G3a to G5) present for a minimum of 3 months. MedlinePlus describes levels below 60 for 3 or more months as a sign of CKD. One low result does not settle it. KDIGO's practice point is not to assume chronicity from a single abnormal eGFR. NKF says your healthcare professional determines your stage. A fair question for your team is whether a low result has been confirmed by a repeat test.

What do the G1 to G5 categories mean?

They are KDIGO's GFR bands: G1 is 90 or above (normal or high), G2 is 60 to 89 (mildly decreased), G3a is 45 to 59 (mildly to moderately decreased), G3b is 30 to 44 (moderately to severely decreased), G4 is 15 to 29 (severely decreased) and G5 is below 15 (kidney failure). The G band is only half of a stage. KDIGO classifies CKD by cause, GFR category and albuminuria category, so the other half comes from a urine test, uACR, and a stage reads like G3a, A1.

What is the race-free 2021 CKD-EPI equation?

It is the equation the National Kidney Foundation recommends for estimating GFR in adults, and it leaves race out. In September 2021 a joint task force of NKF and the American Society of Nephrology (ASN) published its final report, recommending the 2021 CKD-EPI creatinine equation without a race variable and calling for immediate use in all US laboratories. The KDIGO 2024 guideline on evaluating and managing CKD says race should not be used to compute eGFR. It notes that the older 2009 CKD-EPI creatinine equation included race, while the 2021 version uses creatinine, age and sex. NIDDK supports the task force's recommendation and says earlier equations that adjusted for race are no longer recommended. The task force also called for more routine use of cystatin C, especially to confirm eGFR in adults who are at risk for or have CKD, because combining the two markers is more accurate than either alone.

Why can an older and a newer report show different numbers?

Because the equation may have changed, not only your kidneys. Announcing the 2021 equation, NKF and ASN said the new approach may report a different eGFR and could alter the stage of kidney disease in some people. KDIGO says dropping the race coefficient makes the 2021 equation give a small overestimate of GFR in non-Black individuals and a small underestimate in Black individuals. NIDDK says health care teams compare eGFR values calculated with the same equation, and that when values from different equations are compared, some of the change could come from the equation rather than from kidney function. It suggests labs name the equation on the report and date any switch. Older reports may also show a capped figure, such as 60 or more, where newer ones print an exact number. With results from several practices or years, you could ask which equation each lab used and when it changed.

Why can one eGFR result dip?

Because an eGFR is an estimate, and things other than kidney function can move creatinine. KDIGO says that when eGFR changes, clinicians should consider other causes, such as a recent meat meal, a change in muscle mass, extreme activity or an error in the lab assay. In one study it cites, a cooked meat or fish meal raised creatinine enough to lower eGFR by about 20 ml/min per 1.73 m² in that study group. The estimate also has a range built in. NIDDK says that even for the most accurate equations, only about 90% of estimates fall within 30% of measured GFR. Certain medicines can affect results as well, MedlinePlus says. NKF's list of questions for your doctor includes "Could dehydration, illness, or infection affect this number?" You could also ask whether a large meat meal or a hard workout before the draw might have played a part.

How do I read an eGFR trend?

Across several results, calculated the same way. NIDDK says health care teams should use eGFR trends, when available, rather than a single estimate, and that kidney function is best read from trends over time using the same equation. For people with CKD, KDIGO's practice point is that a change in eGFR of more than 20% on a later test exceeds the expected variability and warrants evaluation, and the first step with any change is to repeat the test. No clear threshold defines a clinically relevant change, and overreading small changes may lead to unnecessary changes in care. On timing, the 2024 guideline's practice points are to assess GFR at least once a year in people with CKD, and more often for individuals at higher risk of progression when measurement will impact therapeutic decisions.

What could I ask my care team about my eGFR?

You could ask which equation your lab used, whether a low result has been repeated, how your latest number compares with earlier ones and when the next test is due. NKF's question list includes "Has my eGFR changed since my last test?", "Do I need this test repeated?" and "How often should my eGFR be checked?" NKF suggests bringing copies of past lab results, since looking at trends over time is often more helpful than looking at one number.

Sources

• NIDDK: Chronic Kidney Disease Tests & Diagnosis (last reviewed October 2016): NIDDK says a blood test that checks how well your kidneys are filtering your blood is called GFR, and that GFR stands for glomerular filtration rate.
• NIDDK: Chronic Kidney Disease Tests & Diagnosis (last reviewed October 2016): NIDDK says creatinine is a waste product from the normal breakdown of muscles in your body, and that providers use the amount of creatinine in your blood to estimate your GFR.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.2.4.1 rationale, p. S188): KDIGO says the 2021 CKD-EPI creatinine equation was refitted without race and includes creatinine, age, and sex.
• MedlinePlus: Estimated Glomerular Filtration Rate (eGFR) and GFR Tests: MedlinePlus says eGFR may also be calculated using the level of cystatin C, a protein that many cells in your body make, and that in certain cases creatinine and cystatin levels are both used to calculate eGFR in adults.
• MedlinePlus: Estimated Glomerular Filtration Rate (eGFR) and GFR Tests: MedlinePlus says a measured GFR test is complicated and not widely available, so providers usually use an estimate (eGFR).
• NIDDK: Glomerular Filtration Rate Equations, Laboratory Working Group (last reviewed May 2025): NIDDK says that regardless of the equation used, the eGFR value is an estimate and is not a precise measure of kidney function.
• National Kidney Foundation: Estimated Glomerular Filtration Rate (eGFR) (last updated February 5, 2026): NKF says that in adults the normal eGFR number is usually more than 90.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Table 2, p. S137): KDIGO's GFR category G1 is 90 or above (ml/min per 1.73 m2), described as normal or high (Table 2).
• NIDDK: Chronic Kidney Disease Tests & Diagnosis (last reviewed October 2016): NIDDK says a GFR of 60 or more is in the normal range.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (CKD nomenclature heat map, p. S126): KDIGO's grid is color coded, with green meaning low risk (if no other markers of kidney disease, no CKD); G2, 60-89, sits in the green cells at the lowest albuminuria level.
• NIDDK: Demographics & eGFR Accuracy, Laboratory Working Group (last reviewed May 2025): NIDDK's table of population mean eGFRs from the National Health and Nutrition Examination Survey (NHANES) III runs from 116 at ages 20-29 to 75 at age 70 and older, and NIDDK says kidney function declines with age in adults.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Table 2, p. S137): KDIGO reports GFR categories in ml/min per 1.73 m2 (Table 2).
• MedlinePlus Medical Encyclopedia: Glomerular filtration rate (review date 7/1/2025): MedlinePlus says normal value ranges may vary slightly among different laboratories.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Table 1, p. S137): KDIGO's criteria for chronic kidney disease (either of the following present for a minimum of 3 months) list decreased GFR, a GFR below 60 ml/min per 1.73 m2 (GFR categories G3a-G5) (Table 1).
• MedlinePlus Medical Encyclopedia: Glomerular filtration rate (review date 7/1/2025): MedlinePlus says levels below 60 mL/min/1.73 m2 for 3 or more months are a sign of chronic kidney disease.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.1.3.2, p. S149): KDIGO's practice point says not to assume chronicity based upon a single abnormal level for eGFR and ACR (Practice Point 1.1.3.2).
• National Kidney Foundation: Estimated Glomerular Filtration Rate (eGFR) (last updated February 5, 2026): NKF says your healthcare professional determines your stage of kidney disease based on your level of kidney function shown by your eGFR or mGFR.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Table 2, p. S137): KDIGO's GFR categories are G1 90 or above (normal or high), G2 60-89 (mildly decreased), G3a 45-59 (mildly to moderately decreased), G3b 30-44 (moderately to severely decreased), G4 15-29 (severely decreased) and G5 below 15 (kidney failure) (Table 2).
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (CKD nomenclature, p. S126; example notation p. S144): KDIGO says CKD is classified based on Cause, GFR category (G1-G5) and Albuminuria category (A1-A3), abbreviated CGA, and its text writes combined categories as, for example, CKD G3a, A1.
• National Kidney Foundation: CKD-EPI Creatinine Equation (2021): NKF says the recommended method for estimating GFR in adults from the National Kidney Foundation is the 2021 CKD-EPI equations.
• National Kidney Foundation press release: NKF and ASN Release New Way to Diagnose Kidney Diseases (September 23, 2021): NKF's September 23, 2021 release says the NKF-ASN Task Force released its final report, published online in the American Journal of Kidney Diseases (AJKD) and the Journal of the American Society of Nephrology (JASN), recommending the eGFR 2021 CKD-EPI creatinine equation that estimates kidney function without a race variable.
• Delgado C, et al. A Unifying Approach for GFR Estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. J Am Soc Nephrol 2021;32(12):2994-3015 (PMC8638402; Significance Statement and Recommendations): The NKF-ASN Task Force report recommends immediate implementation of the CKD-EPI creatinine equation refit without the race variable in all laboratories in the United States.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.2.4.2, p. S188): KDIGO's practice point says use of race in the computation of eGFR should be avoided (Practice Point 1.2.4.2).
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.2.4.1 rationale, p. S188): KDIGO says the 2009 CKD-EPI creatinine equation includes creatinine, age, race, and sex.
• NIDDK: Glomerular Filtration Rate Equations, Laboratory Working Group (last reviewed May 2025): NIDDK says it supports the National Kidney Foundation-American Society of Nephrology Task Force's recommendation to calculate eGFR using CKD-EPI equations that do not include a race coefficient, listing the 2021 CKD-EPI creatinine equation first.
• NIDDK: Demographics & eGFR Accuracy, Laboratory Working Group (last reviewed May 2025): NIDDK says previous eGFR equations also adjusted for race, and that these equations are no longer recommended and are provided for reference.
• Delgado C, et al. A Unifying Approach for GFR Estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. J Am Soc Nephrol 2021;32(12):2994-3015 (PMC8638402; Significance Statement and Recommendations): The NKF-ASN Task Force recommends national efforts to facilitate increased, routine, and timely use of cystatin C, especially to confirm eGFR in adults who are at risk for or have CKD, because combining creatinine and cystatin C is more accurate than either marker alone.
• National Kidney Foundation press release: NKF and ASN Release New Way to Diagnose Kidney Diseases (September 23, 2021): NKF's September 23, 2021 release says the new approach may report a different eGFR and could alter the stage of kidney diseases in some people.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.2.4.1 rationale, p. S188): KDIGO says that, as a consequence of not including the Black race coefficient, the 2021 CKD-EPI creatinine equation leads to a small overestimate of GFR in non-Black individuals and a small underestimate in Black individuals.
• NIDDK: Glomerular Filtration Rate Equations, Laboratory Working Group (last reviewed May 2025): NIDDK says health care teams compare eGFR values calculated using the same equation, and that if values calculated using different equations are compared, some of the change could be a consequence of using different equations rather than a change in kidney function.
• NIDDK: Glomerular Filtration Rate Equations, Laboratory Working Group (last reviewed May 2025): NIDDK suggests laboratories clearly identify the equation used when reporting eGFR and, if the system has changed equations, indicate the date of the change.
• NIDDK: Glomerular Filtration Rate Equations, Laboratory Working Group (last reviewed May 2025): NIDDK says the increased accuracy of the CKD-EPI equations allows for more precise reporting of eGFR values than would have previously been reported as 60 or more (≥ 60 mL/min/1.73 m2), and suggests reporting eGFR as an exact whole number.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.2.2.5, p. S182): KDIGO says that when evaluating a change in eGFR over time, there are potential causes other than a true change in GFR, such as changes in non-GFR determinants of the filtration markers or analytical errors in the assays, and that providers should consider whether there has been a change in non-GFR determinants (e.g., a recent meat meal, change in muscle mass or extreme activity) (Practice Point 1.2.2.5).
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 1.2.2.4 rationale, p. S182): KDIGO says one study showed an increase in serum creatinine of approximately 0.23 mg/dl after a cooked meat or fish meal, which in the study population was equivalent to a decrease in eGFR of approximately 20 ml/min per 1.73 m2.
• NIDDK: Factors Affecting eGFR Accuracy, Laboratory Working Group (last reviewed May 2025): NIDDK says that for even the most accurate estimating equations, only about 90% of GFR estimates are within 30% of the measured GFR of the study population.
• MedlinePlus: Estimated Glomerular Filtration Rate (eGFR) and GFR Tests: MedlinePlus says certain medicines can affect your eGFR results.
• National Kidney Foundation: Estimated Glomerular Filtration Rate (eGFR) (last updated February 5, 2026): NKF's list of questions to ask your doctor about eGFR includes "Could dehydration, illness, or infection affect this number?"
• NIDDK: Glomerular Filtration Rate Equations, Laboratory Working Group (last reviewed May 2025): NIDDK says that, given the eGFR value is an estimate, health care teams should use eGFR trends, when available, rather than a single point estimate.
• NIDDK: Factors Affecting eGFR Accuracy, Laboratory Working Group (last reviewed May 2025): NIDDK says kidney function is best interpreted by looking at trends in an individual's eGFR over time, using the same estimating equation, rather than by focusing on a single eGFR value.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 2.1.3, p. S196): KDIGO's practice point says that for people with CKD a change in eGFR of more than 20% on a subsequent test exceeds the expected variability and warrants evaluation (Practice Point 2.1.3).
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Chapter 2.1 rationale, p. S196): KDIGO says the initial evaluation of an observed change in either eGFR or ACR should be to repeat the test(s) to determine whether the change is clinically significant progression or within biological and analytical variability.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Point 2.1.1 rationale, p. S196): KDIGO says no clear threshold defines a clinically relevant change in GFR or albuminuria, and that overinterpretation of small changes may lead to unnecessary changes in clinical management.
• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int 2024;105(4S) (Practice Points 2.1.1-2.1.2, p. S196): KDIGO's practice points say to assess GFR at least annually in people with CKD (Practice Point 2.1.1), and more often for individuals at higher risk of CKD progression when measurement will impact therapeutic decisions (Practice Point 2.1.2).
• National Kidney Foundation: Estimated Glomerular Filtration Rate (eGFR) (last updated February 5, 2026): NKF's list of questions to ask your doctor about eGFR includes "Has my eGFR changed since my last test?", "Do I need this test repeated?" and "How often should my eGFR be checked?"
• National Kidney Foundation: Estimated Glomerular Filtration Rate (eGFR) (last updated February 5, 2026): NKF says that if you have copies of past lab results, bring them with you, and that looking at trends over time is often more helpful than looking at one number.

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