eGFR Manual Calculation

CKD-EPI 2021 Creatinine Equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{age} \times (1.012 \text{ if female}) \]

Estimated GFR (eGFR):

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1. What Is eGFR Manual Calculation?

Manual calculation of estimated glomerular filtration rate using the CKD-EPI 2021 creatinine equation provides accurate assessment of kidney function from serum creatinine levels, age, and gender.

2. How Does The Calculator Work?

The calculator uses the CKD-EPI 2021 equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{age} \times (1.012 \text{ if female}) \]

Where:

\( Scr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male)
\( \alpha \) — -0.241 (female) or -0.302 (male)
\( age \) — Age in years
1.012 — Female multiplier

Explanation: This updated 2021 equation provides improved accuracy in estimating glomerular filtration rate across different population groups.

3. Importance Of eGFR Calculation

Details: Accurate GFR estimation is essential for detecting chronic kidney disease, monitoring disease progression, and adjusting medication dosages based on renal function.

4. Using The Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. Ensure all values are valid (creatinine > 0, age between 1-120 years).

5. Frequently Asked Questions (FAQ)

Q1: What Is The CKD-EPI 2021 Equation?
A: The CKD-EPI 2021 creatinine equation is an updated version that provides more accurate eGFR estimates, particularly in populations with preserved kidney function.

Q2: How Does This Differ From Previous Equations?
A: This version uses updated coefficients (142, -1.200, 0.9938) and gender-specific parameters for improved accuracy across diverse populations.

Q3: When Should Serum Creatinine Be Measured?
A: Morning fasting samples are preferred, but random samples are acceptable. Avoid testing after high-protein meals or intense physical activity.

Q4: What Are The Limitations Of This Equation?
A: Accuracy may be reduced in extreme age groups, pregnant women, amputees, and individuals with rapidly changing kidney function or unusual muscle mass.

Q5: Can This Be Used For Medication Dosing?
A: While useful for initial assessment, critical medication dosing decisions may require measured GFR in specific clinical situations.