Kidney function after nephrectomy — what happens to creatinine and eGFR once a kidney is removed

You have not simply lost half your kidney function. That is the arithmetic people do in their heads on the ward, and it is not how the kidneys behave. Filtering capacity is shared unevenly and held in reserve, and the kidney that stays behind responds to the extra workload by enlarging and filtering more — a process that starts within days of the operation and carries on over the months that follow. Most people who have a kidney removed for cancer go on to live an ordinary life with the one that remains. The wider picture of the diagnosis sits on our kidney cancer guide; this page stays with the numbers.

The early dip is the operation, not a complication. In the first days after surgery, creatinine usually rises and the eGFR calculated from it falls. Part of that is the loss of filtering tissue, and part of it is everything else that happens around an operation — fasting, fluid shifts, anaesthetic, blood loss, pain relief. This is why the reading taken on day one or two is the least informative number you will ever be given, and why nobody should draw a conclusion from it.

Then it climbs back, and levels off. As the remaining kidney adapts, the number improves from that early low point and then plateaus. Most of that improvement happens in the first few months, and where it settles becomes your new baseline — the line every later result is measured against. It is often lower than your pre-operative figure, and frequently in the band laboratories flag as reduced. That is a description of your filtering reserve, not a verdict about your health, and for most people it never translates into a symptom.

How much you keep depends on what was done and where you started. A partial nephrectomy removes the tumour with a margin and leaves the healthy kidney tissue around it filtering, so it preserves more function than removing the whole kidney; that is precisely why it is preferred wherever it is technically and oncologically safe. Beyond that, the eGFR you started with, your age, your blood pressure and whether you live with diabetes all shape where you land. Your pre-operative bloods are therefore the single most useful piece of paper you own — what they measure is set out on our page about kidney function tests before treatment.

Reduced function is not the same as kidney failure. Laboratories flag an eGFR under 60 because that is the threshold used to define chronic kidney disease, but the definition also requires the result to be sustained for about three months and read alongside your urine protein result. Sitting below that line after a nephrectomy is common, is usually stable, and is managed by protecting the kidney you have rather than by treating the number. Whether it ever leads anywhere further is covered on our page on dialysis and CKD risk after kidney removal, and the day-to-day practicalities on living with one kidney after kidney cancer.

Where this care happens. The follow-up bloods, the urine protein and albumin tests, the blood-pressure and diabetes review, the surveillance imaging and the long-term function monitoring are all delivered in-house at CION and read with you by a medical oncologist rather than filed. The operation itself — partial or radical nephrectomy, open, laparoscopic or robotic — along with tumour ablation and PET-CT, is coordinated for CION patients with specialist urology, uro-oncology and interventional radiology partners, and may be billed at the partner centre. NCCN guidance expects kidney function to be documented before treatment and followed afterwards, which is exactly what this schedule is for.

Five things move a creatinine or eGFR result after surgery without your remaining kidney having changed at all. Any of them is worth raising before you accept a number as your new normal:

• Fluid balance. Fasting before a test, a hot day, poor intake, vomiting or diarrhoea all concentrate the blood and push creatinine up temporarily. Being over-filled after surgery can flatter it the other way.
• Weight and muscle mass. Creatinine comes from muscle, so weight loss during recovery can lower the number and hide a real fall in filtering, while regaining muscle can raise it without anything getting worse.
• Medicines. Anti-inflammatory painkillers, some blood-pressure tablets, certain antibiotics and several over-the-counter supplements all shift the result. Take your full list to every appointment, including anything bought without a prescription.
• Being unwell on the day. Infection, fever, a recent contrast scan or a spell back in hospital can all produce a one-off reading that recovers on repeat testing.
• A different laboratory. Different labs report eGFR using different equations, so comparing a result from one against another can invent a fall or a rise that never happened. Where you can, keep testing in one place.

If a number on your discharge summary or follow-up report has worried you and nobody has gone through it, ask. Book a free consultation and have your before-and-after results read together.

The bloods, urine tests, blood-pressure and diabetes review, medicine review and follow-up monitoring on this list are delivered in-house at CION. Kidney surgery, robotic surgery, tumour ablation and PET-CT are coordinated for you with specialist urology, uro-oncology and interventional radiology partners and may be billed at the partner centre. We put an indicative cost in writing before anything is booked, and check Aarogyasri, CGHS, ESI and insurance eligibility with you first.

When to pick up the phone rather than wait. A creatinine that keeps climbing across repeat tests, a clear fall in how much urine you are passing, new swelling of the ankles or face, breathlessness, persistent vomiting, drowsiness or confusion, visible blood in the urine, or fever and pain over the remaining kidney all warrant contacting your team promptly rather than waiting for the next appointment. None of these means the cancer has come back, but all of them need looking at now rather than in six weeks.

If your function numbers are the thing on your mind, these are the pages worth reading next — one on what the tests measured before your operation, one on the day-to-day realities afterwards, and one on the question almost everybody wants answered and few people ask out loud.

• Kidney function tests (creatinine, eGFR) before treatment — what each test on the pre-operative panel measures, and why your baseline matters so much afterwards.
• Living with one kidney after kidney cancer — work, exercise, travel, medicines and the practical precautions that actually make a difference.
• Will I need dialysis? CKD risk after kidney removal — what reduced function does and does not lead to, and who needs closer watching.
• Kidney cancer — the complete guide — types, stages, risk factors and symptoms, in one place.
• Kidney cancer treatment in Hyderabad — how treatment is planned at CION, what is delivered in-house, and what is coordinated with specialist partners.

Not sure which of these applies to your situation? Book a free consultation and ask an oncologist directly.

Know what your numbers are doing, not just what they say

Every case at CION goes to a tumour board, not one doctor's opinion, and protecting the kidney you keep is part of the plan from the first appointment.

This page is general health information about kidney function, creatinine and eGFR after a kidney or part of a kidney has been removed for cancer. It is not a diagnosis and it cannot replace a specialist review of your own results. Only a doctor who has seen your operation notes, your bloods, your urine result, your scans, your medicines and you can say what your numbers mean and what should happen next. If your creatinine keeps rising, or you are passing much less urine, swelling, breathless, drowsy, feverish, or have visible blood in your urine, contact your team promptly rather than waiting for the next appointment.