eGFR in Blood Test: What It Means for Your Kidneys Guide
eGFR (estimated glomerular filtration rate) is a blood test that measures how well your kidneys are filtering waste from your blood. It is calculated using your creatinine level, age, gender, and race, providing a key indicator of kidney function. Today, eGFR remains the cornerstone for assessing kidney health and detecting chronic kidney disease (CKD) early.
Understanding eGFR and Kidney Function
Your kidneys filter about 120–150 quarts of blood daily, removing toxins and excess fluids. The eGFR value estimates the volume of blood filtered per minute per 1.73 m² of body surface area. A normal eGFR is typically 90 mL/min/1.73 m² or higher. As kidney function declines, eGFR drops, signaling potential damage or disease.
How eGFR Is Calculated
Laboratories use formulas such as the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation, which incorporates serum creatinine, age, sex, and sometimes race. Today, many U.S. labs have adopted race-free equations to reduce disparities. The result is reported as a single number in mL/min/1.73 m².
Normal eGFR Ranges
While normal ranges vary slightly by lab, the National Kidney Foundation defines these general categories:
| eGFR (mL/min/1.73 m²) | Kidney Function Status |
|---|---|
| ≥90 | Normal or high |
| 60–89 | Mildly decreased (often without symptoms) |
| 45–59 | Mild to moderate decrease |
| 30–44 | Moderate to severe decrease |
| 15–29 | Severe decrease |
| <15 | Kidney failure (dialysis may be needed) |
What Your eGFR Results Mean
An eGFR below 60 for three months or more indicates chronic kidney disease. The lower the number, the more advanced the stage. Early stages often have no symptoms, making eGFR testing vital for early intervention.
Stages of Chronic Kidney Disease (CKD)
The five CKD stages correlate directly with eGFR ranges:
- Stage 1: eGFR ≥90 with kidney damage (e.g., protein in urine)
- Stage 2: eGFR 60–89 with mild damage
- Stage 3a: eGFR 45–59; Stage 3b: 30–44
- Stage 4: eGFR 15–29 – severe reduction
- Stage 5: eGFR <15 – kidney failure
Factors That Can Affect eGFR
Several variables can temporarily alter eGFR results, including:
- Dehydration or high-protein meals
- Certain medications (e.g., NSAIDs, ACE inhibitors)
- Pregnancy or muscle mass changes
- Acute kidney injury from infection or toxins
- Lab errors or fasting status
Always discuss borderline results with your healthcare provider to confirm whether repeat testing is needed.
Why eGFR Testing Matters today
With rising rates of diabetes and hypertension—the top causes of kidney failure—eGFR screening is more important than ever. The U.S. Preventive Services Task Force now recommends periodic testing for at-risk adults. Early detection can slow progression through lifestyle changes, medication, and monitoring.
Preventive Health and Early Detection
Knowing your eGFR empowers you to take control of your kidney health. Even a mildly decreased result can prompt actions like controlling blood pressure, reducing salt intake, and avoiding nephrotoxic drugs. Regular testing every 12 months is advised for those with risk factors.
Take the Next Step for Your Kidney Health
Ready to check your eGFR? Lab Providers offers a comprehensive kidney function panel that includes eGFR, creatinine, and BUN. Order your test online with no doctor visit required—results delivered securely in 24–48 hours. Order your eGFR blood test now and stay ahead of your health today.
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