eGFR Calculator Medscape

Medscape 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 The Medscape eGFR Equation?

The Medscape eGFR equation estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. This equation provides an alternative method for assessing kidney function with specific coefficients optimized for clinical use.

2. How Does The Calculator Work?

The calculator uses the Medscape 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: This equation provides an alternative approach to GFR estimation with specific coefficients that may offer advantages in certain clinical scenarios.

3. Importance Of eGFR Calculation

Details: Accurate GFR estimation is essential for kidney function assessment, chronic kidney disease diagnosis, and appropriate medication dosing in patients with renal impairment.

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) for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: How Does Medscape eGFR Differ From CKD-EPI?
A: The Medscape equation uses different coefficients (142 vs 141, different alpha values, and 0.9938 vs 0.993) which may provide slightly different estimates in certain populations.

Q2: What Are Normal eGFR Values?
A: Normal eGFR is generally ≥90 mL/min/1.73m². Values below 60 mL/min/1.73m² for 3+ months typically indicate chronic kidney disease.

Q3: When Should Creatinine Be Measured?
A: Morning fasting samples are preferred, but random samples are acceptable. Avoid testing immediately after high-protein meals or intense physical activity.

Q4: Are There Limitations To This Equation?
A: Like other eGFR equations, accuracy may be reduced in elderly patients, extremes of body size, amputees, pregnant women, and those with rapidly changing kidney function.

Q5: Can This Equation Be Used For Drug Dosing?
A: While useful for screening, measured GFR may be necessary for precise drug dosing decisions, especially for medications with narrow therapeutic windows.