eGFR Calculator UKidney

MDRD Equation:

\[ eGFR = 175 \times Scr^{-1.154} \times Age^{-0.203} \times (0.742 \text{ if female}) \times (1.212 \text{ if Black}) \]

Serum Creatinine (Scr):

mg/dL

Age:

years

Gender:

Race:

Estimated GFR (eGFR):

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1. What is the MDRD Equation?

The MDRD (Modification of Diet in Renal Disease) equation estimates glomerular filtration rate (GFR) from serum creatinine, age, sex, and race. It was developed to provide a more accurate assessment of kidney function in patients with chronic kidney disease.

2. How Does the Calculator Work?

The calculator uses the MDRD equation:

\[ eGFR = 175 \times Scr^{-1.154} \times Age^{-0.203} \times (0.742 \text{ if female}) \times (1.212 \text{ if Black}) \]

Where:

\( Scr \) — Serum creatinine (mg/dL)
\( Age \) — Age in years
0.742 — Female multiplier
1.212 — Black race multiplier

Explanation: The equation uses serum creatinine, age, gender, and race to estimate glomerular filtration rate, which reflects kidney function.

3. Importance of eGFR Calculation

Details: Accurate GFR estimation is essential for diagnosing chronic kidney disease, monitoring disease progression, and adjusting medication dosages based on renal function.

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 years).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between MDRD and CKD-EPI equations?
A: MDRD is more accurate in patients with established CKD, while CKD-EPI performs better at higher GFR levels and is less likely to misclassify individuals with normal or mildly reduced kidney function.

Q2: What are the limitations of the MDRD equation?
A: The equation may be less accurate in elderly patients, those with extreme body sizes, pregnant women, and populations with different muscle mass or dietary patterns.

Q3: When is the MDRD equation preferred?
A: MDRD is commonly used in clinical settings for patients with known or suspected chronic kidney disease and for drug dosing adjustments.

Q4: How often should eGFR be monitored?
A: Frequency depends on clinical context - typically every 3-12 months for stable CKD patients, more frequently during acute illness or medication changes.

Q5: Can this calculator be used for children?
A: No, the MDRD equation is validated for adults only. Pediatric patients require age and height-adjusted equations.