eGFR (Creatinine-based)
An estimate of how well your kidneys filter blood, worked out from your creatinine, age and sex.
AI-verified against cited sources. Awaiting expert reviewAlso called eGFR, eGFRcr, TFGeLOINC 98979-8
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What it is
eGFR stands for estimated glomerular filtration rate. Your kidneys filter waste out of your blood, and GFR is how much blood they filter each minute. A routine test can't measure that directly. So the lab estimates it from your blood creatinine level, your age and your sex. Many labs now use the 2021 CKD-EPI equation, which does not use race.
Why it matters
eGFR is the main number clinicians use to describe kidney function. An eGFR below 60 that lasts 3 months or more is one of the standard criteria for chronic kidney disease. Early kidney disease often causes no symptoms, so this number is often how it is first noticed. eGFR is read together with a urine albumin test (uACR), because kidney damage can show up in either one.
If it’s low
A lower eGFR means your kidneys may be filtering less blood than expected for your age. If it stays below 60 for 3 months or more, that meets one of the standard criteria for chronic kidney disease. One low result is not enough to say that. Short-term things such as dehydration, illness or a recent meat-heavy meal can lower the estimate for a while.
Common causes
- Dehydration, or a recent illness with vomiting or diarrhea (often temporary)
- A large cooked-meat or fish meal before the blood draw, or creatine supplements
- Medicines that raise creatinine without changing true kidney function, such as trimethoprim or cimetidine
- Getting older, since eGFR declines gradually with age even in people without kidney disease
- Chronic kidney disease, which is more common with diabetes, high blood pressure and heart disease
- Sudden kidney injury during a serious illness (acute kidney injury)
What can help
- Have the test repeated to confirm it, since one result is rarely enough
- Ask your clinician about a urine albumin test (uACR) and a cystatin C test
- Ask your clinician to review your medicines and supplements, including over-the-counter pain relievers and creatine, and don't stop any on your own
- Keeping blood pressure and blood sugar in the range your clinician recommends supports kidney health
- Not smoking, regular physical activity and a balanced diet support kidney and heart health
If it’s high
Labs don't set an upper limit for eGFR, and young healthy adults often have estimates above 100. A higher number is not always better, though. A very high estimate can come from a low creatinine level caused by low muscle mass or poor nutrition, not from stronger kidneys. KDIGO notes that in large studies, creatinine-based estimates above about 105 were linked to more risk, a pattern not seen with estimates that use cystatin C.
Common causes
- Younger age, since estimates are highest in young adults
- Low muscle mass, frailty or low body weight, which means less creatinine is made
- A low-protein or vegetarian diet
What can help
- Ask your clinician whether a cystatin C test, which doesn't depend on muscle mass, would give a clearer picture if your muscle mass is low
Usual ranges
What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.
The usual range depends on age. Choose an age to see the one that applies.
- 18+60 and above mL/min/1.73 m²
Sources: ARUP Laboratories, Mayo Clinic Laboratories, Kidney International 105(4S):S117-S314, National Kidney Foundation
- 18+60 and above mL/min/1.73 m²
Source: Nemocnice Na Bulovce, Prague
Children and teens 1 ranges
- 2–1790 and above mL/min/1.73 m²
See eGFR by age and sex, with the U.S. survey numbers where they exist.
KDIGO 2024 GFR categories
- G5: kidney failurebelow 15 mL/min/1.73 m²
- G4: severely decreased15 to under 30 mL/min/1.73 m²
- G3b: moderately to severely decreased30 to under 45 mL/min/1.73 m²
- G3a: mildly to moderately decreased45 to under 60 mL/min/1.73 m²
- G2: mildly decreased60 to under 90 mL/min/1.73 m²
- G1: normal or high90 and above mL/min/1.73 m²
If this applies to you
eGFR means a little more for some people. Open the one that fits you.
Gout
The ACR guideline notes that gout is more likely to progress and form tophi in people with moderate to severe CKD. Kidney function also guides which urate-lowering medicine is preferred and how low the starting dose is.
Kidney disease or at risk
eGFR is the main number for how well the kidneys filter. KDIGO 2024 suggests checking it together with a urine albumin test in people at risk, and at least once a year in people with CKD. NIDDK advises a yearly check for people with diabetes.
Age 65 or older
eGFR estimates how well the kidneys filter, and it guides the dose of many medicines the kidneys clear. KDIGO notes that in older adults with low muscle mass, creatinine-based eGFR can overestimate kidney function, which can lead to doses that are too high.
Prediabetes or diabetes
eGFR estimates how well the kidneys filter, and the ADA pairs it with uACR in those yearly kidney checks. Some diabetes medicines, such as metformin, are used at lower doses or avoided when eGFR is low.
Strength training
Most eGFR results are worked out from creatinine, so a very muscular person can get an eGFR that looks lower than their true kidney function. Kidney guidelines list bodybuilding among the reasons a creatinine-based estimate can be off.
On gender-affirming hormones
eGFR is worked out with a sex in the formula, so the number changes depending on which one the lab uses. One review suggests that if either the male or the female estimate points to extra care, clinicians can act on it.
On a GLP-1 medicine
eGFR is worked out from creatinine and shows how well the kidneys filter. The ADA suggests monitoring kidney function when these medicines are started or the dose goes up in people with reduced kidney function who report severe stomach side effects.
Taking HIV PrEP
The CDC judges kidney function on PrEP pills by estimated creatinine clearance, worked out with the Cockcroft-Gault formula from creatinine, age, sex and an ideal weight based on height. The eGFR on most lab reports comes from a different equation and is scaled to a standard body size, so the two numbers can differ.
Taking lithium
Long-term lithium is linked to kidney changes, so kidney function is checked before starting and during treatment. NICE suggests eGFR every 6 months, and more frequent lithium checks if eGFR falls over 2 or more tests.
Taking methotrexate
eGFR is worked out from creatinine and checked with it. The BSR lists a low eGFR, or a large rise in creatinine over 12 months, among the results to act on.
How common is your level?
NHANES describes the US civilian, non-institutionalized population, not a 'healthy' reference group. People with disease, on medication, fasting or not (except fasting-subsample markers), smokers and so on are all included. A percentile says where a value sits among Americans of that sex and age, not whether it is normal.
Use the left and right arrow keys to read each age. Shift moves five years.
Reference data derived from CDC/NCHS National Health and Nutrition Examination Survey (NHANES), cycles 2015-2016, 2017-March 2020 (pre-pandemic), August 2021-August 2023. Analysis by bloodtesttracker.com; not endorsed by CDC, NCHS or HHS.
Explore eGFR by age and sex: every percentile as a table, with a download.
What can affect your result
- Age: average eGFR falls gradually with age. National Kidney Foundation averages are about 116 at ages 20 to 29, 107 at 30 to 39, 99 at 40 to 49, 93 at 50 to 59, 85 at 60 to 69 and 75 at 70 and older, with wide variation between people
- Muscle mass: low muscle mass can make eGFR look better than it is, and very high muscle mass or bodybuilding can make it look worse
- Diet: cooked meat or fish, very high-protein diets, vegetarian or low-protein diets and creatine supplements change creatinine
- Hydration and illness: dehydration and acute illness can lower eGFR temporarily
- Medicines that change how creatinine is handled, such as trimethoprim and cimetidine
- Pregnancy: the standard equations are less accurate in pregnancy
- The equation your lab uses: CKD-EPI 2021, CKD-EPI 2009 and MDRD give different numbers for the same sample
- Age under 18: the adult equation is not used; pediatric equations apply
- A cooked-meat or fish meal can raise creatinine for several hours and lower the estimate. One study found a rise of about 0.23 mg/dL (20 µmol/L), which equals a drop of about 20 mL/min/1.73 m² in eGFR. KDIGO notes that waiting about 12 hours after meat or fish avoids this, though that can be hard to arrange.
- Creatine supplements, very high-protein diets, vegetarian or low-protein diets, and very low or very high muscle mass shift creatinine independent of kidney function.
- Trimethoprim and cimetidine block creatinine secretion in the kidney tubules and can raise creatinine without a true drop in kidney function.
- The estimate assumes creatinine is steady from day to day. During acute illness or sudden kidney injury it is unreliable.
- Some creatinine methods (Jaffe) can be affected by certain cephalosporin antibiotics, bilirubin and glucose. KDIGO prefers enzymatic creatinine assays.
- Different equations (CKD-EPI 2021, CKD-EPI 2009, MDRD) give different numbers from the same blood sample. Compare results that come from the same equation.
Any time of day. If you can, avoid a large cooked-meat or fish meal in the hours before the blood draw. Can shift within hours to days with a meat-heavy meal, dehydration or illness. Lasting changes in kidney function are judged over at least 3 months.
When to talk to a clinician
Talk with a clinician if your eGFR is below 60, or if it has dropped by more than about 20% from your usual level (KDIGO says that is larger than the expected test-to-test variation in people with kidney disease). KDIGO lists an eGFR below 30 among the reasons to see a kidney specialist. Contact a clinician soon if a low eGFR comes with much less urine than usual, swelling in your legs or feet, nausea or vomiting, or severe tiredness. If your lab flagged the result as urgent, follow its instructions.
Questions you could ask
- Which equation does this lab use, and will my results stay comparable over time?
- How often should my kidney function be checked, given my health conditions?
- Could my muscle mass or diet be making my eGFR look higher than my kidney function really is?
- Would a cystatin C test be useful for me?
- Should we repeat this test to see whether it stays low for 3 months or more?
- Should I also have a urine albumin test (uACR)?
Questions people ask
My report says '>60' or '>90'. What does that mean?
Some labs don't print exact numbers above a cutoff. The equation is less precise when kidney function is high, so the lab reports 'greater than' a set value. It means your estimate was at or above that level.
Why did my eGFR change when my lab switched equations?
Different equations give slightly different numbers for the same blood sample. The 2021 CKD-EPI equation removed the race factor used before, so results can shift. NIDDK suggests tracking trends with results from a single equation.
Is one eGFR below 60 enough to mean I have kidney disease?
No. Chronic kidney disease means signs of kidney damage that last at least 3 months. A single low value can come from dehydration, an acute illness or a recent meat meal, so clinicians usually repeat the test and often check a urine albumin test (uACR) as well.
My eGFR is in the 60s or 70s. Is that a problem?
It depends on your age and on other results. KDIGO calls 60 to 89 'mildly decreased' compared with young adults. Without other signs of kidney damage, such as albumin in the urine, it doesn't meet the criteria for chronic kidney disease. Average eGFR for people in their 60s is about 85 and for people 70 and older is about 75. Your clinician can put it in context.
Can eating meat or taking creatine change my result?
Yes. Cooked meat and fish can raise creatinine for several hours, and creatine supplements can raise it too. Both make the eGFR estimate look lower than your true kidney function. If you want the most accurate number, ask your clinician whether to avoid meat or fish for about 12 hours before the draw.
Show the science and sources
Units
- 1 mL/min/1.73 m² = 1 mL/min/1.73 m²
- 1 mL/min/1.73 m² = 0.01667 mL/s/1.73 m²
For clinicians and researchers
eGFRcr is calculated from IDMS-standardized serum creatinine, age and sex with the CKD-EPI 2021 race-free equation: 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 [if female], with κ 0.7 (female) or 0.9 (male) and α −0.241 (female) or −0.302 (male), Scr in mg/dL. In the validation data (Inker 2021), 85% or more of estimates were within 30% of measured GFR, the equation overestimated measured GFR by a median 3.9 mL/min/1.73 m² in non-Black participants and underestimated it by 3.6 in Black participants. Creatinine depends on muscle mass, diet, tubular secretion and extrarenal elimination, so KDIGO 2024 recommends eGFRcr-cys when eGFRcr is likely to be inaccurate and the result will change decisions (1C), and measured GFR when more accuracy is needed. KDIGO also asks labs to report eGFR as a whole number in mL/min/1.73 m², flag values below 60 as low, use enzymatic creatinine assays where possible and use the same equation across a region. GFR categories are G1 90 or above, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 below 15; G1 and G2 do not meet CKD criteria without other evidence of kidney damage. In pooled cohort data, risk for outcomes not driven by creatinine rises at eGFRcr above about 105, the reference group being eGFR 90–104 with ACR below 10 mg/g. In people with CKD, a change in eGFR of more than 20% on a later test exceeds expected variability. Pediatric labs use bedside Schwartz or CKiD U25 equations. Results from older equations (MDRD, CKD-EPI 2009, with or without a race coefficient) are not interchangeable with 2021 values.
LOINC 98979-8 (primary), 62238-1, 33914-3, 77147-7, 69405-9, 48642-3. Specimen: calculated.
Sources
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney International 105(4S):S117-S314 (2024)
- CKD-EPI Creatinine Equation (2021), National Kidney Foundation
- New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race, New England Journal of Medicine (2021)
- Estimated Glomerular Filtration Rate Calculators, NIDDK
- Estimated Glomerular Filtration Rate (eGFR), National Kidney Foundation
- Creatinine With eGFR (test 3005478), ARUP Laboratories
- CRTS1 - Creatinine with Estimated Glomerular Filtration Rate (eGFR), Serum, Mayo Clinic Laboratories
- eGFR (CKD-EPI) - výpočet, Laboratorní příručka Centrální laboratoře NNB, Nemocnice Na Bulovce, Prague (2021)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.