When Do You Need Dialysis?

Few conversations feel heavier than the one where dialysis enters the picture. For most patients, hearing that they may eventually need it feels like the conversation has moved from managing a condition to confronting a new reality. And yet, for millions of people around the world, dialysis is simply what keeps them alive and functioning when their kidneys can no longer do that work on their own.

If you or someone you love is approaching this conversation, understanding what dialysis actually involves, when it becomes necessary, how it works, and what choices you have, can make a real difference. The more you know, the less it feels like something happening to you, and the more it feels like something you can navigate.

What do the kidneys actually do and where does dialysis come in?

Your kidneys are relentless workers. Every single day, they filter roughly 180 litres of blood, removing waste, regulating how much water your body holds, keeping your electrolytes in balance, and helping to control your blood pressure. Most of the time, they do all of this quietly, without you noticing.

When the kidneys begin to fail, all of that stops. Waste products that should be cleared start accumulating in the blood. Fluid builds up where it shouldn't. The body's internal balance becomes increasingly difficult to maintain. This is what kidney failure looks like from the inside.

Dialysis steps in to perform this work artificially. It doesn't heal the kidneys or restore their function; it replaces them, keeping the body stable enough to live.

So, when does dialysis actually become necessary?

There is no single moment where a test result flips and dialysis becomes unavoidable. The decision is more nuanced than that, and it's one that doctors make carefully, in consultation with their patients, over time.

The key measure doctors use is called the eGFR, estimated glomerular filtration rate. Think of it as a percentage of normal kidney function. Dialysis is generally considered when kidney function falls below 10%, but even that isn't a hard rule.

Consider two patients, both at similar kidney function levels. One feels reasonably well, is eating normally, and has stable blood test results. Their doctor may choose to monitor them closely rather than start dialysis immediately. The other has fluid accumulating in their lungs, dangerous shifts in their potassium levels, and is struggling to function day-to-day. They may need to start sooner. The number matters, but so does the full picture.

This is why patients with kidney disease are typically monitored closely by a kidney specialist (a nephrologist) for months or even years before reaching this point. The goal is to be prepared, not caught off guard.

Warning signs that dialysis may be approaching

As kidney function declines, the body usually gives clear signals. If you or someone you care for is experiencing any of the following, it's worth speaking to a doctor promptly:

• Persistent nausea, vomiting, or a significant loss of appetite
• Swelling in the legs, ankles, or feet, or shortness of breath caused by fluid around the lungs
• Dangerous levels of potassium in the blood, which can disrupt heart rhythm
• Severe fatigue, confusion, or difficulty thinking clearly, signs that waste products are affecting the brain
• Blood pressure that remains dangerously high despite medication

None of these symptoms alone means dialysis is inevitable, but taken together, or in combination with worsening blood tests, they are taken seriously.

The two types of dialysis — and how to choose

There are two main types of dialysis, and understanding them helps patients make an informed choice in discussion with their nephrologist. Neither is universally better. The best choice depends on your health, your lifestyle, your home situation, and your personal preferences.

Haemodialysis

In haemodialysis, blood is pumped through the machine, into which the blood is filtered and pumped back into the body. Usually happens in a dialysis centre, and the sessions are typically three times a week, four hours long.

For those who prefer more flexibility, home haemodialysis is an option, done more frequently but for shorter sessions, fitting around your schedule rather than the clinic's.

Peritoneal Dialysis

Peritoneal dialysis works differently, and the blood never leaves the body at all. Instead, a catheter (a small, permanently placed tube) is inserted into the abdomen. A special fluid is introduced through this tube, which draws waste products across the natural membrane lining the abdominal cavity called the peritoneum. That fluid is then drained away, taking the waste with it.

This can be done at home manually at intervals throughout the day, or overnight using an automated machine while you sleep. Many patients find it fits more naturally into a working life.

Your nephrologist will guide you through the options based on your health, lifestyle, home environment and preferences, and the conversation is genuinely a two-way one.

Dialysis as a bridge to transplant

For patients who are eligible, a kidney transplant remains the best long-term outcome. Dialysis, in these cases, is a bridge, a way of staying healthy while waiting for a suitable donor organ.

In some situations, it's possible to receive a transplant before dialysis ever becomes necessary. This is called a pre-emptive transplant, and when it's achievable, it tends to lead to better outcomes than dialysis followed by transplant. If you're approaching end-stage kidney disease, it's worth asking your doctor whether transplant eligibility is something to discuss now.

Conservative management as an alternative

For some patients, particularly older adults managing several serious health conditions at once, dialysis may not be the right choice. The demands of regular treatment can be significant, and for some, the burdens may outweigh the benefits in terms of quality of life.

In these cases, comprehensive conservative care is a genuine alternative. This approach focuses on managing symptoms, maintaining comfort, and preserving quality of life, without kidney replacement therapy. It's a deeply personal decision, made together with family and the medical team, and it deserves to be considered with the same care and respect as any other option.

A final word

Reaching the point where dialysis becomes part of the conversation is not the end of anything. For most patients, it is the beginning of a new chapter, one that, with the right support and information, can still include independence, connection, and a quality of life worth living.

The decisions ahead are real ones, and they carry weight. But they are yours to make, and you won't be making them alone.

Key takeaways

• Dialysis replaces kidney function,  it doesn't cure kidney disease.
• The decision to start is based on symptoms and blood tests together, not a single number.
• There are two types: haemodialysis (machine-based, usually in a clinic) and peritoneal dialysis (at home, using the body's own membrane).
• For eligible patients, kidney transplant, ideally before dialysis starts, remains the gold standard.
• Conservative management is a valid alternative for some patients, focused on comfort and quality of life.