1. What is the NKF Calculator?

The NKF (National Kidney Foundation) calculator estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. It provides a reliable assessment of kidney function using a well-validated equation.

2. How Does the Calculator Work?

The calculator uses the NKF equation:

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: The equation accounts for the non-linear relationship between creatinine and GFR, with different coefficients for different demographic groups.

3. Importance of eGFR Calculation

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

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is the NKF equation used for?
A: The NKF equation is used to estimate glomerular filtration rate (GFR) for assessing kidney function and detecting chronic kidney disease.

Q2: What are normal eGFR values?
A: Normal eGFR is generally ≥90 mL/min/1.73m². Values below 60 mL/min/1.73m² for 3 months or more indicate chronic kidney disease.

Q3: When should serum creatinine be measured?
A: Morning fasting samples are ideal, but random samples are acceptable. Avoid testing after high-protein meals or strenuous exercise.

Q4: Are there limitations to the NKF equation?
A: The equation may be less accurate in elderly patients, those with extreme body weights, amputees, pregnant women, and individuals with rapidly changing kidney function.

Q5: Can this calculator be used for medication dosing?
A: For precise drug dosing, especially with nephrotoxic medications, measured GFR may be required in specific patient populations.