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What Is eGFR?
[PLACEHOLDER] Your introduction to eGFR goes here. Explain what the glomerular filtration rate measures in plain language. Describe the glomeruli in the kidneys, what they filter, and why this rate matters clinically. Mention that eGFR is an estimate derived from a blood test rather than a direct measurement.
[PLACEHOLDER] Continue with why eGFR is used as the primary marker for kidney function in clinical practice. Reference KDIGO guidelines and how eGFR replaced older markers. Mention that a single low eGFR reading doesn't necessarily mean CKD—the diagnosis requires abnormalities present for more than 3 months.
How Is eGFR Calculated?
[PLACEHOLDER] Explain the CKD-EPI 2021 equation in accessible terms. Describe the variables it uses: serum creatinine, age, and biological sex. Explain why creatinine is a good proxy for kidney filtration (it's a muscle metabolism byproduct freely filtered by glomeruli). Note that the 2021 update removed race as a variable.
[PLACEHOLDER] Optionally compare CKD-EPI 2021 to the older MDRD equation and earlier CKD-EPI 2009 formula. Explain when each might be used and why CKD-EPI 2021 is now the preferred standard. You may also mention cystatin C-based equations for specific populations.
💡 Try It Yourself
Enter your serum creatinine, age, and sex into our free GFR calculator to instantly estimate your eGFR using the CKD-EPI 2021 equation.
CKD Stages Explained (G1–G5)
[PLACEHOLDER] Walk through each CKD stage—G1 through G5—with eGFR thresholds, clinical implications, and typical symptoms (or lack thereof in early stages). Note that G1 and G2 require additional markers of kidney damage (e.g., proteinuria) to qualify as CKD. Explain why early detection is critical for slowing progression.
[PLACEHOLDER] Discuss the albuminuria categories (A1, A2, A3) and how they combine with GFR stages to create a risk matrix. Reference the KDIGO heat map. This gives readers a fuller picture of CKD classification beyond just the eGFR number.
| Stage | eGFR | Description |
|---|---|---|
| G1 | ≥ 90 | Normal or High |
| G2 | 60–89 | Mildly Decreased |
| G3a | 45–59 | Mild to Moderate Decrease |
| G3b | 30–44 | Moderate to Severe Decrease |
| G4 | 15–29 | Severely Decreased |
| G5 | < 15 | Kidney Failure |
What Is a Normal eGFR?
[PLACEHOLDER] Define what "normal" means in context. Explain that eGFR naturally declines with age (approximately 1 mL/min/year after age 40) and that an eGFR of 75 in a 70-year-old may be appropriate. Discuss the concept of eGFR trajectory—a single measurement is less meaningful than trends over time.
[PLACEHOLDER] Address common misconceptions: a high eGFR is not always better, acute illness can temporarily lower eGFR, and muscular individuals may have higher creatinine that falsely lowers their calculated eGFR. Mention when cystatin C testing provides a more accurate picture.
What Causes Low eGFR?
[PLACEHOLDER] List and explain common causes of reduced eGFR: diabetic nephropathy, hypertensive nephropathy, glomerulonephritis, polycystic kidney disease, recurrent kidney infections, lupus nephritis, and medication-induced nephrotoxicity. Distinguish between acute kidney injury (AKI) and chronic kidney disease (CKD).
[PLACEHOLDER] Discuss reversible vs. irreversible causes. Explain how some acute causes—dehydration, NSAIDs, contrast dye—can be treated, while others represent permanent nephron loss. Provide guidance on follow-up testing intervals recommended by KDIGO based on CKD stage.
Can You Improve Your eGFR?
[PLACEHOLDER] Discuss evidence-based strategies for preserving or improving kidney function: blood pressure control (target <130/80 mmHg per KDIGO 2021), glycemic control in diabetics (HbA1c target), SGLT2 inhibitors and their nephroprotective effects, dietary protein moderation, RAAS blockade with ACE inhibitors or ARBs, and avoidance of nephrotoxins.
[PLACEHOLDER] Address lifestyle factors: hydration, smoking cessation, weight management, and exercise. Emphasize that while established nephron loss cannot be recovered, progression can be significantly slowed with proper management. Include a CTA to use the calculator to track changes over time.
📊 Track Your Progress
After starting a new treatment or lifestyle change, use our GFR calculator to monitor your eGFR over time. Always work with your nephrologist to interpret trends.
When to See a Doctor
[PLACEHOLDER] Provide clear guidance on when to seek medical care: first-time eGFR below 60, rapidly declining eGFR (more than 5 mL/min/year), eGFR below 30 (referral to nephrologist recommended), accompanying symptoms like edema, foamy urine, or hypertension, and when to consider kidney biopsy or transplant evaluation.
[PLACEHOLDER] Emphasize that this calculator and article are educational tools, not diagnostic instruments. Reiterate the importance of working with a healthcare provider for interpretation, repeat testing, additional labs (BMP, CBC, urinalysis, imaging), and treatment planning.
The Bottom Line
[PLACEHOLDER] Write a concise, reassuring conclusion. Reinforce key takeaways: eGFR is a critical but context-dependent number, trends matter more than single readings, and early action can preserve kidney function for decades. End with a strong call-to-action linking back to the calculator and encouraging consultation with a nephrologist.
Use our free, clinically-referenced GFR calculator to estimate your kidney function in seconds—no registration required.
Open the GFR Calculator →References
- Inker LA, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737–1749.
- KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl. 2013;3(1):1–150.
- Stevens PE, Levin A; Kidney Disease: Improving Global Outcomes CKD Guideline Development Work Group Members. Evaluation and management of chronic kidney disease: synopsis of the kidney disease: improving global outcomes 2012 clinical practice guideline. Ann Intern Med. 2013;158(11):825–830.
[PLACEHOLDER] Add your own references and citations here to support the content you write for each section above.