Kidneys filter waste and excess fluids from the blood, a function measured by the Glomerular Filtration Rate (GFR). When kidney function significantly declines, dialysis becomes necessary. This article explains GFR, how dialysis works, and clarifies if dialysis improves GFR or replaces kidney function.
What GFR Measures
The Glomerular Filtration Rate (GFR) measures how quickly blood is filtered by the glomeruli, tiny filtering units in the kidneys. It indicates kidney function and is a primary tool for diagnosing and staging chronic kidney disease (CKD). A higher GFR suggests healthier kidneys, while a lower GFR indicates impaired filtering.
GFR values categorize kidney disease stages. A GFR of 90 milliliters per minute per 1.73 square meters (mL/min/1.73m²) or higher is considered normal. As GFR declines, kidney disease progresses, with a GFR below 15 mL/min/1.73m² signifying kidney failure, often requiring intervention.
Healthcare providers estimate GFR (eGFR) using a blood test that measures creatinine levels, a muscle waste product. This level, along with age, sex, and body size, helps calculate eGFR. While direct GFR measurement is complex, eGFR offers a reliable assessment for routine kidney health evaluation.
How Dialysis Functions
Dialysis is a medical procedure that removes waste products, excess fluids, and toxins from the blood when kidneys can no longer function effectively. It acts as an artificial substitute for the kidney’s natural filtering processes. Without dialysis, these harmful substances would accumulate, leading to severe health complications.
Two primary types of dialysis exist: hemodialysis and peritoneal dialysis. Hemodialysis circulates blood outside the body through a dialyzer, an artificial kidney machine. This machine filters blood, removing wastes and extra fluid, before returning it to the body.
Peritoneal dialysis uses the patient’s abdominal lining, the peritoneum, as a natural filter. A cleansing solution, called dialysate, is introduced into the abdominal cavity via a catheter. Waste and excess fluid from the blood pass into this solution across the peritoneal membrane, which is then drained and replaced.
Does Dialysis Improve GFR?
Dialysis does not improve the Glomerular Filtration Rate. GFR measures the kidneys’ native filtering capacity. Dialysis is a replacement therapy; it performs the functions of failed kidneys but does not restore or heal damaged kidney tissue.
Kidney damage requiring dialysis is irreversible. While dialysis effectively removes waste and fluid, it cannot repair kidney impairments. Therefore, the kidneys’ natural filtering ability, measured by GFR, remains unchanged or may continue to decline despite treatment.
Even after starting dialysis, any remaining kidney function may continue to diminish over time. This does not signify an improvement in the kidneys’ intrinsic filtering ability. Dialysis is a supportive measure, not a regenerative one for kidney function.
What Dialysis Achieves
Dialysis sustains life for individuals with kidney failure. It effectively substitutes for lost kidney functions, removing accumulated toxins like urea and creatinine.
Beyond waste removal, dialysis also regulates electrolyte balance, maintaining mineral levels like potassium, sodium, and calcium. It manages excess fluid, preventing overload that can cause swelling and heart or lung complications.
While dialysis does not restore kidney function, it significantly improves patient quality of life by alleviating symptoms associated with kidney failure. Patients often experience reduced fatigue, nausea, and shortness of breath. This treatment provides essential life support, allowing individuals to manage their condition and lead extended lives.