The question of when kidney function loss requires dialysis is highly relevant for those facing chronic kidney disease. This decision point marks the transition to End-Stage Renal Disease (ESRD), a condition where the kidneys can no longer sustain the body’s needs. Kidney health and disease progression are tracked using the estimated Glomerular Filtration Rate (eGFR). This metric provides a clear, numerical representation of the remaining kidney function, guiding both patients and physicians in preparing for treatment.
How Kidney Function is Measured
Kidney function is primarily gauged by the estimated Glomerular Filtration Rate (eGFR), which represents the rate at which the kidneys filter waste from the blood. A laboratory measures creatinine, a waste product from muscle breakdown, in a blood sample. This level is then applied to a formula factoring in a person’s age and sex. A healthy eGFR is typically 90 milliliters per minute per 1.73 square meters or higher, often considered 100% function.
The eGFR value is the basis for classifying the five stages of Chronic Kidney Disease (CKD). Stage 1 indicates normal function (eGFR 90 or above), while Stage 5 represents the most severe loss (eGFR below 15). For example, an eGFR of 45 means the kidneys are working at roughly 45% capacity. This staging system allows doctors to monitor disease progression and initiate pre-emptive care.
The Specific Threshold for Dialysis
End-Stage Renal Disease (ESRD) is diagnosed when the eGFR consistently falls below 15 milliliters per minute per 1.73 square meters, classifying it as CKD Stage 5. Dialysis is not always started immediately at this level. Current medical guidelines suggest that if patients are asymptomatic, dialysis can be safely delayed.
Dialysis initiation typically occurs when the eGFR drops further, often reaching between 5 and 10 milliliters per minute per 1.73 square meters. This represents less than 10% of a healthy kidney’s filtering capacity. Planning for this transition, including creating access for dialysis, begins much earlier, sometimes when the eGFR is still in the 20s. Starting dialysis too early (eGFR above 10) does not provide a survival benefit and may increase the risk of complications. The decision balances reaching a functionally impaired state with avoiding unnecessary early intervention.
Symptoms That Trigger Dialysis Sooner
Although eGFR provides a numerical guideline, the decision to begin dialysis is often driven by the patient’s clinical status and severe symptoms. These symptoms, collectively known as uremia, result from the buildup of toxins and waste products the kidneys can no longer eliminate. Uremic symptoms compel immediate treatment, even if the eGFR is slightly above the typical threshold.
Dialysis is urgently indicated by several severe complications:
- Severe hyperkalemia, an excessive level of potassium that can cause life-threatening heart rhythm abnormalities.
- Intractable fluid overload, where diuretics are no longer effective at removing excess fluid, potentially leading to pulmonary edema.
- Uremic pericarditis, which is inflammation of the sac surrounding the heart, causing chest pain.
- Debilitating uremic symptoms, such as persistent nausea, vomiting, loss of appetite (anorexia), and profound fatigue.
When these complications cannot be managed with diet or medication, dialysis becomes necessary to remove toxins and restore the body’s internal balance.
Treatment Options Beyond Dialysis
The two primary forms of treatment for End-Stage Renal Disease are dialysis and kidney transplantation. Dialysis is a life-sustaining therapy that artificially removes waste and excess fluid from the blood. This includes hemodialysis, which uses a machine to filter blood externally, and peritoneal dialysis, which uses the patient’s abdominal lining as a natural filter, often performed at home.
Kidney transplantation is generally the preferred long-term solution, offering the best quality of life and survival rates, but it requires a compatible donor organ. Patients may remain on dialysis while awaiting a transplant.
A final pathway is conservative management, also known as supportive or palliative care. This focuses on symptom relief and comfort without using dialysis or transplantation. This option is often chosen by patients who are elderly, frail, or have severe health conditions where the burdens of aggressive treatment outweigh the benefits. The choice of treatment is a shared decision, tailored to the individual patient’s health status and personal wishes.