Mdcalc GFR Creatinine Clearance Calculator Formula

MDCalc GFR CrCl Formula (CKD-EPI):

\[ GFR = 141 \times \min(SCr/\kappa,1)^\alpha \times \max(SCr/\kappa,1)^{-1.209} \times 0.993^{Age} \times (1.018 \text{ if female}) \times (1.159 \text{ if black}) \]

Serum Creatinine (SCr):

mg/dL

Age:

years

Gender:

Race:

Estimated GFR:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the MDCalc GFR CrCl Formula?

The MDCalc GFR CrCl formula is based on the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation that estimates glomerular filtration rate (GFR) from serum creatinine, age, sex, and race. It's widely used in clinical practice for assessing kidney function.

2. How Does the Calculator Work?

The calculator uses the MDCalc GFR CrCl formula:

\[ GFR = 141 \times \min(SCr/\kappa,1)^\alpha \times \max(SCr/\kappa,1)^{-1.209} \times 0.993^{Age} \times (1.018 \text{ if female}) \times (1.159 \text{ if black}) \]

Where:

\( SCr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male)
\( \alpha \) — -0.329 (female) or -0.411 (male)
\( Age \) — Age in years
1.018 — Female multiplier
1.159 — Black race multiplier

Explanation: The equation provides a more accurate estimation of kidney function by accounting for non-linear relationship between creatinine and GFR, with different coefficients for different demographic groups.

3. Importance of GFR Calculation

Details: Accurate GFR estimation is essential for diagnosing chronic kidney disease, determining disease stage, guiding medication dosing, and assessing overall kidney health.

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 GFR and CrCl?
A: GFR (glomerular filtration rate) and CrCl (creatinine clearance) are related but not identical measures of kidney function. This calculator estimates GFR using creatinine values.

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

Q3: When is the best time to measure creatinine?
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 formula?
A: Less accurate in extremes of age/weight, amputees, pregnant women, and those with rapidly changing kidney function or unusual muscle mass.

Q5: Can this be used for medication dosing?
A: While useful for many medications, some drugs may require more precise GFR measurement (e.g., via iohexol clearance) in certain populations.