GFR CKD EPI Calculator

CKD-EPI Equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{age} \times (1.012 \text{ if female}) \]

Estimated GFR (eGFR):

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1. What is the GFR CKD EPI Calculator?

The GFR CKD EPI calculator estimates glomerular filtration rate (GFR) using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation based on serum creatinine, age, and gender. This provides an accurate assessment of kidney function.

2. How Does the Calculator Work?

The calculator uses the CKD-EPI equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{age} \times (1.012 \text{ if female}) \]

Where:

\( Scr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male)
\( \alpha \) — -0.241 (female) or -0.302 (male)
\( age \) — Age in years
1.012 — Female multiplier

Explanation: The equation accounts for the non-linear relationship between creatinine and GFR, with different coefficients for different demographic groups.

3. Importance of eGFR Calculation

Details: Accurate GFR estimation is crucial for diagnosing chronic kidney disease, determining disease stage, and guiding medication dosing decisions.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. All values must be valid (creatinine > 0, age between 1-120 years).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between this and other CKD-EPI equations?
A: This specific equation uses coefficients of 142, -1.200, and 0.9938 with a female multiplier of 1.012, providing optimized accuracy for certain populations.

Q2: What are normal eGFR values?
A: Normal GFR is generally ≥90 mL/min/1.73m², though values naturally decline with age. Values below 60 for 3+ months indicate chronic kidney disease.

Q3: When is the best time to measure creatinine?
A: Morning fasting samples are ideal, but random samples are acceptable. Avoid testing after meat-heavy meals or vigorous exercise.

Q4: Are there limitations to this equation?
A: The equation may be less accurate in extremes of age and weight, amputees, pregnant women, and those with rapidly changing kidney function.

Q5: Can this calculator be used for medication dosing?
A: While useful for screening, precise drug dosing may require measured GFR (e.g., via iohexol clearance) in specific clinical situations.