Chronic Kidney Disease Stages Based on Glomerular Filtration Rate (GFR): A Comprehensive Guide
Understanding kidney health is crucial for early detection and effective management of renal impairment. One of the most reliable indicators of kidney function is the glomerular filtration rate (GFR), which measures how well the kidneys filter waste from the blood. As kidney function declines, GFR values drop, allowing healthcare professionals to classify chronic kidney disease (CKD) into distinct stages. This classification helps guide treatment decisions and predict disease progression.
The Evolution from Traditional Renal Failure Classification to Modern CKD Staging
In the past, kidney dysfunction was broadly categorized into acute and chronic forms, with further divisions such as compensation phase, decompensation phase, renal failure stage, and uremic stage. These terms described the gradual loss of kidney function based on clinical symptoms and lab markers like creatinine levels. However, this system lacked precision and consistency in predicting outcomes.
Today, the medical community has largely adopted a more standardized approach: the five-stage model of chronic kidney disease (CKD I–V), defined primarily by estimated glomerular filtration rate (eGFR). This evidence-based framework offers a clearer picture of kidney health and enables timely interventions.
What Is Glomerular Filtration Rate (GFR)?
Glomerular filtration rate (GFR) reflects the volume of blood filtered by the glomeruli each minute. In healthy adults, normal GFR ranges between 90 and 120 mL/min/1.73m². When GFR falls below certain thresholds, it signals impaired kidney function. The eGFR is calculated using blood creatinine levels, age, sex, and race, making it a non-invasive yet highly informative diagnostic tool.
Stage I: Normal or High Kidney Function (eGFR ≥ 90 mL/min)
This stage indicates that kidney function is within the normal range, but other signs—such as proteinuria (protein in urine), hematuria (blood in urine), or structural abnormalities—may suggest early kidney damage. Patients at this stage often show no symptoms, highlighting the importance of routine screening for those at risk, including individuals with diabetes or hypertension.
Stage II: Mild Decline in Kidney Function (eGFR 60–89 mL/min)
At this point, kidney function is slightly reduced, but many people remain asymptomatic. Detection usually occurs during evaluations for other conditions. Monitoring becomes essential here, as uncontrolled risk factors can accelerate progression to more severe stages.
Stage III: Moderate Kidney Disease (eGFR 30–59 mL/min)
Divided into IIIa (45–59) and IIIb (30–44), this stage marks a significant decline in filtration capacity. Common complications begin to emerge, including anemia, bone disorders, and high blood pressure. Patients may start experiencing fatigue, swelling, or changes in urination patterns. Early referral to a nephrologist is recommended to slow disease progression through lifestyle modifications and medication.
Stage IV: Severe Kidney Impairment (eGFR 15–29 mL/min)
Kidney function is critically low at this stage. The risk of developing end-stage renal disease (ESRD) increases substantially. Planning for renal replacement therapy—including hemodialysis, peritoneal dialysis, or kidney transplantation—should begin now. Multidisciplinary care involving dietitians, vascular surgeons, and transplant specialists improves long-term outcomes.
Stage V: End-Stage Renal Disease (eGFR < 15 mL/min)
Also known as uremia, this final stage signifies near-total kidney failure. Without intervention, toxic waste accumulates in the bloodstream, leading to life-threatening complications. At this point, patients typically require dialysis or a kidney transplant to survive. Symptoms may include nausea, confusion, shortness of breath, and extreme fatigue.
Treatment Options for Advanced Kidney Disease
When kidney function drops below 15 mL/min, replacing lost filtration becomes essential. Hemodialysis uses a machine to filter blood externally, usually performed three times weekly. Peritoneal dialysis leverages the lining of the abdomen to remove toxins and excess fluid, offering greater flexibility for home-based treatment. Ultimately, kidney transplantation remains the most effective long-term solution, providing better quality of life and survival rates compared to lifelong dialysis.
Early diagnosis and proactive management are key to preserving kidney function and delaying the need for invasive therapies. Regular monitoring of eGFR, controlling underlying conditions like diabetes and hypertension, and adopting a kidney-friendly lifestyle can significantly improve prognosis for individuals at any stage of chronic kidney disease.