Tool World

eGFR Calculator

Estimate glomerular filtration rate

The eGFR Calculator is a vital tool for anyone interested in monitoring and assessing kidney health. It computes the estimated Glomerular Filtration Rate (eGFR) using a formula that considers your serum creatinine level along with your age, gender, and race. This estimation is essential for determining how well your kidneys are functioning, as it reflects the rate at which your kidneys are able to filter waste from your blood. Accurate eGFR results can help detect early stages of kidney dysfunction, enabling you and your healthcare provider to take necessary precautions. Using the eGFR calculator is straightforward; simply input the required information, and the tool will provide you with an estimated result in seconds. Regular assessments of your eGFR can help in managing conditions that affect kidney health, such as diabetes or hypertension. By keeping track of your eGFR over time, you can work with your healthcare provider to make informed decisions regarding your lifestyle and treatment plans aimed at preserving kidney function.

Inputs

Provide the following 3 values to run the eGFR Calculator:

  • Serum Creatinine (mg/dL) [number] (required)
  • Age (years) [number] (required)
  • Sex [select] (required)

What it calculates

This tool returns:

  • eGFR (mL/min/1.73m²) — primary result
  • CKD Stage
  • Formula

Worked example

For the sample inputs below:

  • Serum Creatinine (mg/dL): 100
  • Age (years): 10
  • Sex: male

the eGFR Calculator produces:

  • eGFR: 0.5 mL/min/1.73m²
  • CKD Stage: G5 Kidney Failure
  • Formula: CKD-EPI 2021

How it works

The result is derived through the following steps:

  1. kappa = sex === 'female' ? 0.7 : 0.9
  2. alpha = sex === 'female' ? -0.241 : -0.302
  3. sexFactor = sex === 'female' ? 1.012 : 1
  4. minCr = min(creatinine / kappa, 1)
  5. maxCr = max(creatinine / kappa, 1)
  6. egfr = 142 * pow(minCr, alpha) * pow(maxCr, -1.200) * pow(0.9938, age) * sexFactor
  7. stage = egfr >= 90 ? 'G1 Normal' : egfr >= 60 ? 'G2 Mild' : egfr >= 45 ? 'G3a Mild-Mod' : egfr >= 30 ? 'G3b Mod-Severe' : egfr >= 15 ? 'G4 Severe' : 'G5 Kidney Failure'

Frequently Asked Questions

What does eGFR stand for?

eGFR stands for estimated Glomerular Filtration Rate, a test used to assess kidney function.

Why is the eGFR important?

eGFR is important because it helps identify kidney disease early, enabling timely intervention and management.

How is eGFR calculated?

eGFR is usually calculated using a formula that considers your age, gender, race, and serum creatinine level.

What factors can affect my eGFR results?

Factors such as age, muscle mass, hydration status, and certain medications can affect eGFR results.

How often should I check my eGFR?

You should check your eGFR annually if you have risk factors for kidney disease, such as diabetes or high blood pressure.