Calculation of eGFR in Kidney Function

eGFR 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 eGFR Calculation for Kidney Function?

The eGFR (estimated glomerular filtration rate) calculation is used to assess kidney function by estimating the rate at which blood is filtered by the glomeruli in the kidneys. This specific equation provides an accurate measurement of kidney function based on serum creatinine levels, age, and gender.

2. How Does the Calculator Work?

The calculator uses the eGFR 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 serum creatinine and glomerular filtration rate, with different coefficients for males and females to provide accurate kidney function assessment.

3. Importance of eGFR Calculation

Details: Accurate eGFR calculation is essential for detecting early kidney disease, monitoring kidney function over time, determining appropriate medication dosages, and assessing overall renal health status.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. Ensure all values are valid (creatinine > 0, age between 1-120 years). Use recent laboratory results for accurate calculations.

5. Frequently Asked Questions (FAQ)

Q1: What is the clinical significance of eGFR?
A: eGFR helps in early detection of chronic kidney disease, guides treatment decisions, and monitors disease progression over time.

Q2: What are the normal eGFR ranges?
A: Normal eGFR is typically ≥90 mL/min/1.73m². Values between 60-89 may indicate mild kidney impairment, while values below 60 for 3+ months suggest chronic kidney disease.

Q3: When should eGFR be measured?
A: eGFR should be measured during routine health checkups, when kidney disease is suspected, before starting nephrotoxic medications, and for monitoring known kidney conditions.

Q4: Are there limitations to this equation?
A: This equation may be less accurate in elderly patients, those with extreme body mass indices, pregnant women, and individuals with rapidly changing kidney function.

Q5: How often should eGFR be monitored?
A: Frequency depends on individual risk factors and existing conditions. High-risk individuals may need annual testing, while those with established kidney disease may require more frequent monitoring.