Kidney Health Australia eGFR Calculator

CKD-EPI Equation:

\[ eGFR = 141 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.209} \times 0.993^{age} \times (1.018 \text{ if female}) \times (1.159 \text{ if black}) \]

Serum Creatinine (Scr):

mg/dL

Age:

years

Gender:

Race:

Estimated GFR (eGFR):

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1. What Is The Kidney Health Australia eGFR Calculator?

The Kidney Health Australia eGFR Calculator uses the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2009 equation to estimate glomerular filtration rate (GFR) from serum creatinine, age, sex, and race. This calculator provides a more accurate assessment of kidney function than older equations, especially at higher GFR levels.

2. How Does The Calculator Work?

The calculator uses the CKD-EPI 2009 equation:

\[ eGFR = 141 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.209} \times 0.993^{age} \times (1.018 \text{ if female}) \times (1.159 \text{ if black}) \]

Where:

\( eGFR \) — Estimated glomerular filtration rate (mL/min/1.73m²)
\( Scr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male)
\( \alpha \) — -0.329 (female) or -0.411 (male)
\( age \) — Age in years
1.018 — Female multiplier
1.159 — Black race multiplier

Explanation: The equation accounts for non-linear relationship between creatinine and GFR, with different coefficients for different demographic groups as specified in the CKD-EPI 2009 formula.

3. Importance Of eGFR Calculation

Details: Accurate GFR estimation is crucial for diagnosing chronic kidney disease, determining disease stage, and guiding medication dosing according to Kidney Health Australia guidelines.

4. Using The Calculator

Tips: Enter serum creatinine in mg/dL, age in years, select gender and race. All values must be valid (creatinine > 0, age between 1-120). The calculator follows Kidney Health Australia recommendations for eGFR calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why Use CKD-EPI Instead Of MDRD?
A: CKD-EPI is more accurate at higher GFR levels (>60 mL/min/1.73m²) and less likely to misclassify people with mildly reduced kidney function, as recommended by Kidney Health Australia.

Q2: What Are Normal eGFR Values?
A: Normal is generally ≥90 mL/min/1.73m², though values decline with age. Below 60 for 3+ months indicates CKD according to Kidney Health Australia guidelines.

Q3: When Should Creatinine Be Measured?
A: Morning fasting sample is ideal, but random samples are acceptable. Avoid testing after meat-heavy meals or vigorous exercise as per Kidney Health Australia recommendations.

Q4: Are There Limitations To This Equation?
A: Less accurate in extremes of age/weight, amputees, pregnant women, and those with rapidly changing kidney function. Kidney Health Australia provides specific guidance for these populations.

Q5: Should This Be Used For Drug Dosing?
A: For precise drug dosing, measured GFR (e.g., via iohexol clearance) may be needed in certain populations. Consult Kidney Health Australia guidelines for specific recommendations.