What is Calculated eGFR

What Is Calculated eGFR

eGFR Calculation Formula:

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

Estimated GFR (eGFR):

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1. What Is Calculated eGFR?

Calculated eGFR (estimated Glomerular Filtration Rate) is a mathematical estimation of kidney function based on serum creatinine levels, age, and gender. It provides a standardized measure of how well the kidneys are filtering waste from the blood.

2. How Does The Calculator Work?

The calculator uses the eGFR calculation formula:

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

Where:

\( eGFR \) — Estimated Glomerular Filtration Rate (mL/min/1.73m²)
\( Scr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male, unitless)
\( \alpha \) — -0.241 (female) or -0.302 (male, unitless)
\( Age \) — Age in years
1.012 — Female multiplier

Explanation: This equation calculates estimated glomerular filtration rate based on serum creatinine levels, accounting for age and gender differences in muscle mass and creatinine production.

3. Importance Of eGFR Calculation

Details: eGFR calculation is essential for assessing kidney function, detecting early stages of chronic kidney disease, monitoring disease progression, and guiding treatment decisions and medication dosing.

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). The calculator will provide the estimated glomerular filtration rate.

5. Frequently Asked Questions (FAQ)

Q1: What Does eGFR Measure?
A: eGFR measures how well your kidneys are filtering waste from your blood, expressed as milliliters per minute per 1.73 square meters of body surface area.

Q2: What Are Normal eGFR Values?
A: Normal eGFR is generally 90 mL/min/1.73m² or higher. Values between 60-89 may indicate mild kidney damage, while values below 60 for three months or more indicate chronic kidney disease.

Q3: Why Is Age A Factor In eGFR Calculation?
A: Kidney function naturally declines with age, so the calculation adjusts for this expected decrease to provide age-appropriate reference ranges.

Q4: How Often Should eGFR Be Calculated?
A: Frequency depends on individual risk factors, but generally annually for people with diabetes, hypertension, or family history of kidney disease.

Q5: Can eGFR Be Used For All Populations?
A: While useful for most adults, eGFR calculations may be less accurate in extremes of age, pregnancy, severe malnutrition, or rapidly changing kidney function.