1. What is the MDRD GFR 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 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
• 1.212 — African American race multiplier

Explanation: The equation accounts for the inverse relationship between creatinine and GFR, with adjustments for demographic factors that affect muscle mass and creatinine production.

3. Importance of GFR Calculation

Details: GFR estimation is essential for diagnosing and staging chronic kidney disease, monitoring disease progression, and adjusting medication dosages for renal clearance.

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).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between MDRD and CKD-EPI equations?
A: CKD-EPI is generally more accurate at higher GFR levels (>60 mL/min/1.73m²) while MDRD may underestimate GFR in healthier individuals.

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

Q3: When was the MDRD equation developed?
A: The MDRD equation was developed in 1999 based on data from the Modification of Diet in Renal Disease study.

Q4: Are there limitations to the MDRD equation?
A: It's less accurate in extremes of age, body size, and muscle mass, and in populations with normal or near-normal kidney function.

Q5: Should I use MDRD or CKD-EPI?
A: CKD-EPI is now preferred for clinical use, but MDRD remains important for research and when comparing with older studies.