eGFR Calculator Equation

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 eGFR Calculator Equation?

The eGFR Calculator Equation estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. This equation provides an accurate assessment of kidney function based on the latest CKD-EPI research methodology.

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 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. The eGFR value helps healthcare providers assess kidney function and make informed clinical 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). For best results, use recent laboratory values and ensure accurate demographic information.

5. Frequently Asked Questions (FAQ)

Q1: What is the clinical significance of eGFR?
A: eGFR provides an estimate of kidney function and is essential for detecting, monitoring, and managing chronic kidney disease.

Q2: What are normal eGFR values?
A: Normal eGFR is generally ≥90 mL/min/1.73m². Values between 60-89 may indicate mildly reduced kidney function, while values below 60 for 3+ months indicate chronic kidney disease.

Q3: How often should eGFR be calculated?
A: Frequency depends on clinical context. For screening, once yearly may be sufficient. For patients with known kidney disease, more frequent monitoring is recommended.

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

Q5: Can this calculator be used for children?
A: This specific equation is validated for adults. Pediatric eGFR calculations require different equations and considerations.