eGFR CKD-EPI 2009 Calculator
Estimate glomerular filtration rate using the original 2009 CKD-EPI creatinine equation for adults.
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Îş = 0.7 female; 0.9 male
α = -0.329 female; -0.411 male
Female coefficient = 1.018
Original Black coefficient = 1.159
What is the CKD-EPI 2009 Equation?
The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was developed to estimate glomerular filtration rate from serum creatinine while improving accuracy compared with the older MDRD equation, particularly at higher levels of GFR.
The original 2009 creatinine equation uses serum creatinine, age and sex. The original equation also included a coefficient for Black patients.
The result is reported as an estimated GFR normalized to a body surface area of 1.73 m².
eGFR GFR Categories
| eGFR | Category | Description |
|---|---|---|
| ≥90 | G1 | Normal or high |
| 60–89 | G2 | Mildly decreased |
| 45–59 | G3a | Mildly to moderately decreased |
| 30–44 | G3b | Moderately to severely decreased |
| 15–29 | G4 | Severely decreased |
| <15 | G5 | Kidney failure |
Important Clinical Considerations
A single reduced eGFR does not by itself establish chronic kidney disease. CKD generally requires evidence of reduced kidney function or kidney damage that persists for at least three months.
Interpretation should consider the patient's clinical condition, previous creatinine and eGFR values, urine albumin-to-creatinine ratio, medications and other relevant laboratory findings.
CKD-EPI 2009 vs Current Race-Free Equations
The CKD-EPI 2021 creatinine equation does not use a race coefficient and is generally preferred when a current race-free creatinine-based equation is required.
This calculator is therefore particularly useful for education, historical comparison, research datasets and situations in which the original CKD-EPI 2009 equation is specifically requested.
Factors That Can Affect Creatinine-Based eGFR
| Factor | Potential Effect |
|---|---|
| Muscle mass | Low or high muscle mass can make creatinine-based estimates less representative of true GFR. |
| Acute kidney injury | Creatinine may not be in steady state, limiting the reliability of creatinine-based eGFR. |
| Diet | Recent dietary intake can influence serum creatinine. |
| Certain medications | Some drugs can alter creatinine production or tubular creatinine secretion. |
| Extremes of body composition | Creatinine-based equations may be less reliable in selected patients with unusual body composition. |
eGFR CKD-EPI 2009 Calculator - Frequently Asked Questions
What does CKD-EPI stand for?
CKD-EPI stands for Chronic Kidney Disease Epidemiology Collaboration, which developed equations for estimating glomerular filtration rate.
What does the CKD-EPI 2009 calculator measure?
It estimates GFR from serum creatinine, age and sex using the original 2009 CKD-EPI creatinine equation.
What is the normal eGFR?
An eGFR of 90 mL/min/1.73 m² or higher is generally categorized as G1, although eGFR must be interpreted together with other evidence of kidney health.
Is an eGFR below 60 always kidney disease?
Not necessarily from a single result. Persistent reduction in GFR for at least three months, or other evidence of kidney damage, is important when assessing CKD.
Why is creatinine entered in mg/dL?
The original CKD-EPI 2009 equation uses standardized serum creatinine expressed in mg/dL. The calculator automatically converts µmol/L to mg/dL when that unit is selected.
Does CKD-EPI 2009 use race?
The original 2009 equation included a coefficient of 1.159 for Black patients. This race-based coefficient is retained in this calculator only for historical or research purposes.
Is CKD-EPI 2009 still the preferred equation?
It is an older equation. Current clinical practice generally favors race-free equations such as CKD-EPI 2021 when an appropriate current creatinine-based equation is required.
Can eGFR be used during acute kidney injury?
Creatinine-based eGFR equations assume relatively stable creatinine production and are less reliable when serum creatinine is rapidly changing.
Medical Disclaimer: This calculator is intended for educational, research and clinical reference purposes. The CKD-EPI 2009 equation provides an estimate of GFR and should not be interpreted as a direct measurement of kidney function. The original equation included a race-based coefficient that is retained here for historical and research purposes. Current clinical practice may recommend a race-free equation such as CKD-EPI 2021. Clinical decisions should not be based on this calculator alone. Healthcare professionals should consider the patient's clinical condition, laboratory trends, urine albuminuria and other relevant findings.
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