eGFR (MDRD) (Calc)

eGFR (MDRD)

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 kidney function, with different coefficients for different demographic groups.

3. Importance of eGFR Calculation

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

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 kidney disease, 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, pregnant women, individuals with extremes of body size, and those with rapidly changing kidney function.

Q3: When was the MDRD equation developed?
A: The MDRD equation was developed in 1999 and has been widely used for estimating GFR in clinical practice.

Q4: Is the MDRD equation validated for all populations?
A: While widely used, the equation may require validation or adjustment for specific ethnic groups or populations not represented in the original study cohort.

Q5: Can MDRD be used for drug dosing?
A: For precise drug dosing, especially with narrow therapeutic windows, measured GFR may be preferred over estimated GFR in certain clinical situations.