Creatinine Clearance Calculator CKD EPI

CKD-EPI Equation:

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

Serum Creatinine (SCr):

mg/dL

Age:

years

Gender:

Race:

Estimated Creatinine Clearance (CrCl):

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1. What is the CKD-EPI Creatinine Equation?

The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation estimates creatinine clearance (CrCl) from serum creatinine, age, sex, and race. It provides a more accurate assessment of kidney function than older equations, especially at higher CrCl levels.

2. How Does the Calculator Work?

The calculator uses the CKD-EPI equation:

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

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 accounts for non-linear relationship between creatinine and CrCl, with different coefficients for different demographic groups.

3. Importance of CrCl Calculation

Details: Accurate CrCl estimation is crucial for assessing renal function, determining drug dosing adjustments, and evaluating kidney disease progression.

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: Why use CKD-EPI instead of MDRD?
A: CKD-EPI is more accurate at higher CrCl levels (>60 mL/min/1.73m²) and less likely to misclassify people with mildly reduced kidney function.

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

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: 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 CrCl (e.g., via 24-hour urine collection) may be needed in certain populations.