Calculated Gfr

GFR Calculator (CKD-EPI 2021)

Male Female

Estimated GFR

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mL/min/1.73 m²

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function calculateGFR() { var cr = parseFloat(document.getElementById('creatinine').value); var age = parseFloat(document.getElementById('age').value); var sex = document.getElementById('sex').value; var resultContainer = document.getElementById('gfr-result-container'); var gfrValueDisplay = document.getElementById('gfr-value'); var gfrStageDisplay = document.getElementById('gfr-stage'); var gfrDescDisplay = document.getElementById('gfr-description'); if (isNaN(cr) || isNaN(age) || cr <= 0 || age = 90) { stage = "Stage 1: Normal"; color = "#48bb78"; desc = "Normal kidney function or kidney damage with normal GFR. High values are usually healthy unless there is evidence of kidney protein leakage."; } else if (roundedGFR >= 60) { stage = "Stage 2: Mildly Decreased"; color = "#81e6d9"; desc = "Mildly decreased kidney function. If other markers like protein in urine are present, this may indicate early stage chronic kidney disease."; } else if (roundedGFR >= 45) { stage = "Stage 3a: Mild-Moderate Decrease"; color = "#ecc94b"; desc = "Mildly to moderately decreased kidney function. This stage often requires monitoring and management of risk factors like blood pressure."; } else if (roundedGFR >= 30) { stage = "Stage 3b: Moderate-Severe Decrease"; color = "#ed8936"; desc = "Moderately to severely decreased kidney function. Increased risk of complications and requires regular medical check-ups."; } else if (roundedGFR >= 15) { stage = "Stage 4: Severely Decreased"; color = "#f56565"; desc = "Severely decreased kidney function. High risk for kidney failure and may require preparation for dialysis or transplant."; } else { stage = "Stage 5: Kidney Failure"; color = "#c53030"; desc = "End-stage kidney disease (ESKD). Dialysis or a kidney transplant is usually necessary at this level."; } gfrStageDisplay.innerText = stage; gfrStageDisplay.style.backgroundColor = color; gfrStageDisplay.style.color = (roundedGFR < 30) ? "white" : "#2d3748"; gfrDescDisplay.innerText = desc; }

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Understanding Your Glomerular Filtration Rate (GFR)

The Glomerular Filtration Rate (GFR) is widely considered the most accurate way to measure how well your kidneys are filtering waste from your blood. Because the direct measurement of GFR is complicated and invasive, clinicians use "estimated GFR" (eGFR) based on levels of waste products like creatinine in the blood.

Why the eGFR Matters

Kidneys filter about 200 quarts of blood daily to produce about 2 quarts of urine. When kidney function declines, waste builds up in the blood. The eGFR helps healthcare providers detect Chronic Kidney Disease (CKD) long before symptoms appear.

The 2021 CKD-EPI Formula

This calculator utilizes the CKD-EPI 2021 Creatinine Equation. This modern standard is designed to be more accurate across diverse populations as it does not include a race-based variable, which was common in older formulas like the MDRD. It relies on three primary inputs:

• Serum Creatinine: A waste product from muscle breakdown. Higher levels typically indicate lower kidney function.
• Age: Kidney function naturally declines slightly as part of the aging process.
• Biological Sex: Men generally have higher muscle mass, leading to higher baseline creatinine levels than women.

Interpreting GFR Stages

Stage	GFR Range	Meaning
Stage 1	90+	Normal function
Stage 2	60-89	Mild decrease
Stage 3a	45-59	Mild-moderate decrease
Stage 3b	30-44	Moderate-severe decrease
Stage 4	15-29	Severe decrease
Stage 5	< 15	Kidney failure

Calculation Examples

Example 1: A 50-year-old male with a serum creatinine of 1.1 mg/dL.
Result: eGFR ≈ 86 mL/min/1.73m² (Stage 2: Mildly Decreased).

Example 2: A 65-year-old female with a serum creatinine of 1.8 mg/dL.
Result: eGFR ≈ 32 mL/min/1.73m² (Stage 3b: Moderate-Severe Decrease).

Note: This calculator is for educational purposes and is based on average population data. Individual health decisions should always be made in consultation with a medical professional. Values can be affected by diet, pregnancy, muscle mass, and certain medications.