1. What is the MDRD Equation?

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

2. How Does the Calculator Work?

The calculator uses the MDRD equation:

Where:

• \( Scr \) — Serum creatinine (mg/dL)
• \( age \) — Age in years
• 0.742 — Female multiplier

Explanation: The equation accounts for the inverse relationship between creatinine and GFR, with adjustment for age-related decline in kidney function and gender differences.

3. Importance of GFR Calculation

Details: GFR estimation is essential for assessing kidney function, diagnosing chronic kidney disease, and determining appropriate medication dosages for patients with reduced kidney function.

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).

5. Frequently Asked Questions (FAQ)

Q1: Why use MDRD equation?
A: The MDRD equation provides a standardized estimate of kidney function and is widely used in clinical practice, though CKD-EPI may be preferred in some cases.

Q2: What are normal GFR values?
A: Normal GFR is generally ≥90 mL/min/1.73m². Values below 60 for 3+ months indicate chronic kidney disease.

Q3: When should creatinine be measured?
A: For most accurate results, measure creatinine in a fasting state and avoid testing after meat-heavy meals or strenuous exercise.

Q4: Are there limitations to MDRD?
A: The equation is less accurate in people with normal or near-normal kidney function, extremes of body size, or rapidly changing kidney function.

Q5: How does MDRD compare to CKD-EPI?
A: CKD-EPI is generally more accurate at higher GFR levels (>60), while MDRD may be more accurate at lower GFR levels.