GFR Calculator By Age

GFR 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):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the GFR Calculator By Age?

The GFR Calculator By Age estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. This specialized equation incorporates age as a key variable to provide accurate assessment of kidney function across different age groups.

2. How Does the Calculator Work?

The calculator uses the GFR 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 specifically accounts for age-related changes in kidney function, with different coefficients optimized for age-based GFR estimation.

3. Importance of GFR Calculation

Details: Accurate age-adjusted GFR estimation is essential for evaluating kidney function across the lifespan, detecting age-related decline, and guiding appropriate clinical decisions.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. The calculator is optimized for age-based GFR estimation with creatinine values > 0 and ages between 1-120 years.

5. Frequently Asked Questions (FAQ)

Q1: Why is age specifically incorporated in this equation?
A: This equation is specifically designed to account for the natural decline in kidney function that occurs with aging, providing more accurate estimates across different age groups.

Q2: How does age affect GFR?
A: GFR naturally declines by approximately 1 mL/min/1.73m² per year after age 40, which is accounted for in the age coefficient (0.9938).

Q3: What are age-specific normal GFR ranges?
A: Normal GFR varies by age: young adults (90-120), middle-aged (70-110), elderly (50-90) mL/min/1.73m².

Q4: Is this equation validated for pediatric use?
A: No, this equation is validated for adults only. Pediatric GFR estimation requires specialized equations.

Q5: How does this compare to other age-based equations?
A: This equation provides optimized coefficients specifically for age-based GFR estimation, with improved accuracy in elderly populations.