Medically Reviewed by Dr. Andrew Stein MD, Consultant Nephrologist (Hospital Kidney Specialist). Last updated: June 2026
Discovering that you or a loved one might need dialysis can feel incredibly overwhelming. It is entirely natural to have questions, and one of the most common things people wonder is: Is there a specific kidney function number that means I must start dialysis?
The short answer is no—it is never based on just a single number. Nephrologists (hospital-based kidney specialists) evaluate a combination of your kidney function metrics, your daily symptoms, and your overall health to determine the precise time to begin treatment.
This comprehensive guide breaks down how this crucial decision is made in clear, straightforward language.
Please Note: This article is specifically written for patients living with Chronic Kidney Disease (CKD). It does not apply to individuals with Acute Kidney Injury (AKI), which is rapid onset of kidney failure that requires different medical management.
Your Glomerular Filtration Rate, or GFR, is a calculation that estimates how efficiently your kidneys are filtering waste and excess fluid from your blood.
In the medical world, GFR is considered one of the most reliable indicators of overall kidney health—the higher your GFR number, the better your kidneys are working.
For a healthy adult, a normal GFR typically ranges between 90 and 120 mL/min. As chronic kidney disease progresses, this number gradually declines.
Your medical team will track your GFR over months and years to monitor the stage of your condition and plan your care effectively.
To help you understand what your specific numbers mean, doctors categorise chronic kidney disease into five distinct stages based on your GFR level:
| GFR Level (mL/min) | Chronic Kidney Disease (CKD) Stage | What It Means for Your Health |
| 90 or higher | Stage 1 | Normal or near-normal kidney function |
| 60–89 | Stage 2 | Mild reduction in kidney function |
| 30–59 | Stage 3 | Moderate reduction in kidney disease |
| 15–29 | Stage 4 | Severe reduction in kidney function |
| Below 15 | Stage 5 | Kidney failure (End-Stage Renal Disease, ESRD) |
Dialysis is generally required when a patient’s GFR drops to 10 to 15 mL/min (Stage 5 CKD). However, entering this numerical range does not mean you will automatically start dialysis the very next day.
Every individual biology is unique. Many patients with a GFR in this lower range can safely and comfortably delay starting dialysis for weeks or even months.
If you feel well, your symptoms are manageable, and your lab values remain stable, your doctor may choose to monitor you closely rather than rushing into treatment.
Creatinine is a natural chemical waste product generated by normal muscle breakdown. Healthy kidneys filter creatinine out of your blood and flush it out through your urine.
If your kidney function begins to decline, your body cannot clear this waste effectively, causing creatinine levels in your blood to rise. Therefore, with creatinine, a lower number is better.
The normal range for blood creatinine is between 60 and 120 mcmol/L.
Because GFR can fluctuate, doctors look closely at your steady creatinine trends alongside your GFR to get a highly accurate picture of your true kidney health.
While your doctor will monitor your creatinine closely, there is no universal ‘tipping point’ number that dictates an immediate need for dialysis.
Most physicians will discuss dialysis when creatinine levels climb over 400 mcmol/L (which generally aligns with Stage 4 or Stage 5 CKD), but the exact number varies wildly because baseline creatinine depends heavily on:
Muscle Mass: People with more muscle naturally produce more creatinine.
Age and Sex: Muscle mass and kidney efficiency naturally shift as we age and differ by sex.
Body Size: Larger individuals naturally have higher baseline levels.
Because of these variations, a smaller, frail individual might feel incredibly ill with a creatinine level of 400 mcmol/L; whilst a larger, muscular individual might feel perfectly fine with a level of 600 or 700 mcmol/L. This is exactly why doctors treat the patient, not just the lab report.
The ultimate question your medical team will ask is: How do you actually feel? In clinical practice, dialysis is typically initiated when kidney failure begins causing tangible, disruptive physical symptoms or dangerous lab imbalances—not purely because a number crossed a line on a page.
As kidney toxins build up in the bloodstream, you may experience several warning signs:
Severe fatigue or overwhelming, chronic weakness
Nausea, vomiting, or a noticeable loss of appetite
Unintended weight loss caused by a lack of desire to eat
Persistent, widespread itching that cannot be relieved by lotions
Brain fog, trouble concentrating, or mild confusion
Shortness of breath, which often points to fluid accumulating in the lungs
Significant swelling (oedema) in your legs, ankles, feet, or face
A distinct, bitter metallic taste in your mouth
Medical Note: Many of these symptoms are non-specific, meaning they can also be caused by other serious health issues like anaemia, heart failure, or liver disease. Your nephrologist will evaluate your symptoms holistically to find the true root cause.
There are times when dialysis must be started urgently, even if a patient’s GFR hasn’t dropped to the absolute lowest level or if they feel relatively okay. These are considered absolute, life-saving medical indications for treatment:
Dangerous Fluid Overload: When excess fluid builds up in the lungs (pulmonary oedema), causing severe shortness of breath that does not improve with standard diuretic medications.
High Blood Potassium (Hyperkalaemia): Severely elevated potassium levels can disrupt the heart’s electrical system, causing life-threatening heart rhythm problems. If diet and medications cannot lower it, dialysis is required.
Severe Blood Acidosis: When the kidneys can no longer balance body acids, the blood becomes dangerously acidic, leading to rapid breathing, extreme weakness, and cardiac complications.
Uraemia (Severe Toxin Buildup): High levels of urea can cause dangerous complications like severe mental confusion, extreme drowsiness, bleeding issues, or painful inflammation around the heart sac (uraemic pericarditis).
Modern nephrology guidelines stress that starting dialysis should always be a collaborative, shared decision between you, your family, and your healthcare team.
The ideal time to start is when kidney symptoms begin to severely diminish your day-to-day quality of life, or when internal clinical complications become unsafe to manage with diet and medication alone.
Medical research shows that starting dialysis prematurely does not extend survival rates and can unnecessarily impact your daily independence. Conversely, waiting too long can expose you to dangerous health risks.
The ultimate goal is to find the ‘sweet spot’—the right time for your unique body. Your care team will carefully balance your symptoms, lab results, lifestyle, and personal goals.
Even if your numbers suggest that you are months or even years away from needing dialysis, planning early is one of the best things you can do for your long-term health and peace of mind. Early education and preparation give you control over your journey.
Advanced planning allows you to:
Carefully weigh your choices between haemodialysis (filtering blood via a machine) and peritoneal dialysis (using the lining of your abdomen to filter waste at home).
Schedule the surgical creation of a permanent dialysis access point—such as an arteriovenous fistula (AVF)—well in advance. This allows the access site plenty of time to heal and mature.
Completely avoid the stress, discomfort, and risks associated with emergency dialysis starts utilising temporary chest catheters.
No Single Trigger: There is no magic GFR or creatinine number that automatically forces an immediate start to dialysis.
The Baseline Framework: Dialysis is generally started when your GFR drops to 10–15 mL/min.
Symptoms Over Numbers: How you feel and how your body is coping with waste elimination matter significantly more than lab sheets alone.
Emergency Indicators: Acute complications like severe fluid in the lungs, unmanageable high potassium, or uraemic confusion require immediate medical intervention.
A Personalised Path: The decision to start is an ongoing partnership between you and your kidney specialist, tailored entirely to your personal comfort, health status, and life goals.
When should acute dialysis be started for acute kidney injury (AKI)?
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