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, and other factors. It provides an assessment of kidney function and is commonly used in clinical practice.

2. How Does the Calculator Work?

The calculator uses the MDRD equation:

Where:

• \( Cr \) — Serum creatinine (mg/dL)
• \( Age \) — Age in years
• \( F \) — Factor multiplier (unitless)

Explanation: The equation accounts for the inverse relationship between creatinine and GFR, with adjustments for age and other factors.

3. Importance of GFR Calculation

Details: Accurate GFR estimation is crucial for diagnosing chronic kidney disease, determining disease stage, and guiding medication dosing.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and factor value. All values must be valid (creatinine > 0, age between 1-120, factors > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the MDRD equation used for?
A: The MDRD equation is used to estimate glomerular filtration rate (GFR) from serum creatinine levels, helping to assess kidney function.

Q2: What are normal GFR values?
A: Normal GFR is generally ≥90 mL/min/1.73m², though values decline with age. Below 60 for 3+ months indicates chronic kidney disease.

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.

Q4: Are there limitations to this equation?
A: The equation may be less accurate in extremes of age/weight, amputees, pregnant women, and those with rapidly changing kidney function.

Q5: Should this be used for drug dosing?
A: For precise drug dosing, measured GFR may be needed in certain populations.