GFR Calculator

- May 10, 2025
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Calculate estimated Glomerular Filtration Rate (eGFR) using the MDRD or CKD-EPI equations. GFR measures how well your kidneys filter blood and helps detect kidney disease.

Patient Information

Laboratory Values

Advanced Options

About GFR and Kidney Function

Glomerular Filtration Rate (GFR) is the best overall measure of kidney function. It estimates how much blood passes through the glomeruli (tiny filters in kidneys) each minute. A declining GFR indicates worsening kidney function.

GFR Classification and CKD Stages
GFR (mL/min/1.73m²) CKD Stage Kidney Function
≥90 Stage 1 (with other evidence of kidney damage) Normal or High
60-89 Stage 2 (with other evidence of kidney damage) Mildly Decreased
45-59 Stage 3a Mildly to Moderately Decreased
30-44 Stage 3b Moderately to Severely Decreased
15-29 Stage 4 Severely Decreased
<15 Stage 5 Kidney Failure
Calculation Methods
  • CKD-EPI Equation (2009): The most accurate method for estimating GFR, especially for higher GFR values (>60 mL/min/1.73m²). Recommended for general clinical use.
  • MDRD Equation (4-variable): An older formula that may underestimate GFR in healthier individuals with values >60 mL/min/1.73m².
Important Notes
  • This calculator provides an estimate of GFR based on serum creatinine. For more accurate kidney function assessment, consult with a healthcare provider.
  • GFR calculations are less reliable at extremes of age and body size.
  • A single GFR measurement should not be used to diagnose kidney disease. Persistent abnormalities for >3 months are needed for chronic kidney disease diagnosis.
  • Additional tests (e.g., urine albumin-to-creatinine ratio) may be needed to fully assess kidney health.

Understanding the GFR Calculator

The GFR Calculator is a helpful tool used to estimate your Glomerular Filtration Rate (GFR). This rate indicates how well your kidneys filter waste from your blood. A lower GFR can signal potential kidney issues. By using either the MDRD or CKD-EPI equations, the calculator provides users with a quick way to assess kidney function based on specific inputs.

Why GFR Matters for Kidney Health

GFR is essential for understanding kidney health. It helps healthcare providers identify different stages of chronic kidney disease (CKD). Knowing your GFR can guide treatment decisions and lifestyle changes. Here are some key reasons why monitoring GFR is vital:

  • Detects kidney dysfunction early on.
  • Guides treatment options for kidney disease.
  • Helps assess the effectiveness of treatments.
  • Informs lifestyle changes to improve kidney health.

Who Should Use the GFR Calculator?

The calculator can be beneficial for a wide range of individuals. Anyone concerned about kidney health, especially those with conditions such as Diabetes or high blood pressure, should consider using it. It’s also useful for healthcare professionals who want to evaluate their patients’ kidney function quickly.

Inputting Your Information

Using the GFR Calculator is straightforward. You’ll need to provide some basic information, such as age, gender, and race. Additionally, you'll enter your serum creatinine level. These details help the calculator provide an accurate estimate of your GFR.

Understanding Your Results

After entering your information, the calculator will show you your estimated GFR along with additional details, such as the CKD stage. These results help you understand your kidney function better. It’s crucial to discuss these results with a healthcare provider for proper interpretation and advice.

GFR Classification and CKD Stages

The results from the GFR Calculator can be classified into stages of chronic kidney disease (CKD). Here’s a brief overview of these stages, which helps in understanding the severity of kidney function:

  • Stage 1: GFR ≥ 90 mL/min/1.73m² (Normal or high)
  • Stage 2: GFR 60-89 mL/min/1.73m² (Mildly decreased)
  • Stage 3: GFR 30-59 mL/min/1.73m² (Moderately decreased)
  • Stage 4: GFR 15-29 mL/min/1.73m² (Severely decreased)
  • Stage 5: GFR < 15 mL/min/1.73m² (Kidney failure)

Choosing the Right Calculation Method

The GFR Calculator allows you to choose between different calculation methods. The CKD-EPI equation is generally preferred as it provides more accurate results, especially when GFR is above 60 mL/min/1.73m². On the Other hand, the MDRD equation may underestimate GFR in healthier individuals. Selecting the right method can significantly affect your results.

Consultation After Calculation

While the GFR Calculator is a great starting point, it isn't a substitute for professional medical advice. If you have concerns about your results, it’s best to consult with a healthcare provider. They can offer more comprehensive tests and interpret your results in the context of your overall health.