Estimated Glomerular Filtration Rate (eGFR) Calculator
Using the CKD-EPI 2009 Creatinine Formula — Quickly Assess Your Kidney Function
Start eGFR Calculation
Formula Details (CKD-EPI 2009)
eGFR = A × (Scr/B)C × 0.993Age × (1.159 if Black)
| Sex | Serum Creatinine (Scr) mg/dL | A | B (κ) | C (α) |
|---|---|---|---|---|
| Female | ≤ 0.7 | 144 | 0.7 | -0.329 |
| > 0.7 | 144 | 0.7 | -1.209 | |
| Male | ≤ 0.9 | 141 | 0.9 | -0.411 |
| > 0.9 | 141 | 0.9 | -1.209 |
Note: The formula is A × (Scr/B)C. For Scr values greater than B, the exponent C is -1.209. For Scr values less than or equal to B, the exponent C is -0.329 for females and -0.411 for males. The factor for age is 0.993Age. If the individual is Black, the entire result is multiplied by 1.159. In the calculator, 'B' corresponds to 'κ' (kappa) and 'C' corresponds to 'α' (alpha) from the original publication.
About Estimated Glomerular Filtration Rate (eGFR) and Kidney Function
What is Estimated Glomerular Filtration Rate (eGFR)?
The Estimated Glomerular Filtration Rate (eGFR) is a key indicator of kidney function. It measures how well your kidneys are filtering waste products from your blood, specifically estimating the volume of blood filtered by the glomeruli (tiny filters in the kidneys) per minute. This eGFR calculator provides this crucial value, standardized to a body surface area of 1.73m² (mL/min/1.73m²). A good eGFR value generally indicates healthy renal function.
Clinical Significance of eGFR Values (Based on KDIGO Guidelines) for Kidney Function
eGFR values are commonly used to stage Chronic Kidney Disease (CKD). Our eGFR calculator helps in understanding these stages:
- Stage G1: eGFR ≥ 90 mL/min/1.73m² (Normal or high kidney function, but other evidence of kidney damage like proteinuria may be present)
- Stage G2: eGFR 60–89 mL/min/1.73m² (Mildly decreased kidney function / renal function)
- Stage G3a: eGFR 45–59 mL/min/1.73m² (Mild to moderately decreased kidney function)
- Stage G3b: eGFR 30–44 mL/min/1.73m² (Moderate to severely decreased kidney function)
- Stage G4: eGFR 15–29 mL/min/1.73m² (Severely decreased kidney function)
- Stage G5: eGFR < 15 mL/min/1.73m² (Kidney failure, often requiring dialysis or kidney transplant)
Note: A single eGFR result from any eGFR calculator does not fully determine your kidney function status. Doctors consider other clinical indicators and medical history for a comprehensive assessment. This GFR calculator is a tool for estimation.
The CKD-EPI 2009 Creatinine Formula used in this eGFR Calculator
This eGFR calculator uses the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation. This formula is widely considered one of the most accurate methods for estimating eGFR in adults, particularly for those with an eGFR > 60 mL/min/1.73m², offering better accuracy than the older MDRD formula. The CKD-EPI 2009 formula accounts for age, sex, serum creatinine level, and race (with an adjustment factor for Black individuals) to assess renal function.
References:
- Levey AS, Stevens LA, Schmid CH, et al. A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009;150(9):604-612. (CKD-EPI Equation for this eGFR calculator)
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl. 2013;3(1):1-150. (Guidelines for interpreting eGFR and kidney function)
LITERATURE
ORIGINAL/PRIMARY REFERENCE
- Levey AS, Stevens LA, Schmid CH, et al. A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009;150(9):604-12.
- Inker LA, Schmid CH, Tighiouart H, et al. Estimating glomerular filtration rate from serum creatinine and cystatin C. N Engl J Med. 2012;367(1):20-9.
- Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin c-based equations to estimate gfr without race. N Engl J Med. Published online September 23, 2021.
CLINICAL PRACTICE GUIDELINES
- KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
- KDIGO 2022 Clinical Practice Guideline for Diabetes Management in Chronic Kidney Disease
Frequently Asked Questions (FAQ) about eGFR Calculator & Kidney Function
eGFR stands for Estimated Glomerular Filtration Rate. It's a measure of how well your kidneys are filtering waste from your blood. An eGFR blood test isn't a direct measurement but an estimate calculated from your serum creatinine level (a waste product), along with your age, sex, and, in the 2009 CKD-EPI formula used by this eGFR calculator, your race.
Your eGFR meaning provides an estimate of your kidney function in mL/min/1.73m². It helps doctors assess your kidney health and stage chronic kidney disease (CKD) if present. It's important to discuss your specific eGFR levels with a healthcare professional.
Generally, an eGFR normal range is 90 mL/min/1.73m² or higher. Values between 60-89 mL/min/1.73m² might be considered mildly decreased if there are other signs of kidney damage. However, "normal" can vary based on age and other factors.
An eGFR blood test low result, or a low eGFR, suggests that your kidneys may not be filtering blood as effectively as they should. This could be an indication of kidney damage or chronic kidney disease (CKD). Further investigation by a doctor is necessary.
When you see what is eGFR in blood test reports, it refers to the estimated glomerular filtration rate calculated from your serum creatinine. It's not a directly measured value but a crucial estimate of your kidney's filtering capacity.
The eGFR CKD-EPI 2009 formula, which this calculator uses, includes a race adjustment (specifically for Black individuals). This was based on population studies suggesting, on average, different serum creatinine levels for the same level of kidney function. The use of race in eGFR calculations is a subject of ongoing discussion, and newer formulas (like the 2021 CKD-EPI) often omit it.
An eGFR blood test high result (e.g., significantly above 120 mL/min/1.73m²) is usually not a cause for concern and typically indicates very good kidney function. However, like any lab result, it should be interpreted by your doctor in the context of your overall health.
An eGFR test is an estimation of filtration rate derived from a blood creatinine test. Other kidney tests might include urine tests (to check for protein or blood), direct GFR measurements (which are more complex and not routinely done), or imaging tests.
eGFR blood work is interpreted alongside the clinical stages of Chronic Kidney Disease (CKD). For instance, an eGFR below 60 for three months or more typically indicates CKD. The lower the eGFR, the more advanced the kidney disease.
While a persistent low eGFR is a key indicator of chronic kidney disease, acute factors can sometimes lower eGFR. These might include dehydration, certain medications (like NSAIDs or some antibiotics), or a sudden illness affecting the kidneys (acute kidney injury). It's crucial to have a doctor evaluate any eGFR low result.
The results provided by this eGFR calculator are for informational purposes only and cannot replace professional medical advice, diagnosis, or treatment for your kidney function.
Calculation results are based on the CKD-EPI 2009 creatinine formula, which has its limitations and may not be suitable for all individuals (e.g., age under 18, pregnancy, abnormal muscle mass, special diets, acute changes in renal function, or issues with serum creatinine measurement).
Any decisions regarding your health status should be made after consulting a qualified healthcare professional. Do not self-diagnose or adjust treatment plans based solely on the results from this eGFR calculator.
This website assumes no liability for any direct or indirect loss arising from the use of the information provided by this GFR calculator tool.