Kidney stone prevention and assessment (metabolic assessment and prevention of nephrolithiasis)
An assessment to work out why you form kidney stones and what changes or treatment can lower the chance of getting more.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- It works out why you form stones and which changes or medicines are most likely to lower your risk.
- It cannot guarantee no more stones; about half of people who have had a stone form another within five years.
- Most of the 'test' is done at home (saving urine, blood tests), then reviewed in clinic over days to weeks.
- The most important and best-proven step for almost everyone is drinking enough fluid to keep urine pale.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Identifies treatable causes such as low urine citrate, high urine calcium or high uric acid.
A full metabolic work-up may not be needed after a single, uncomplicated stone in an otherwise low-risk person.
You collect urine at home over a full day and have blood taken. No discomfort beyond the blood test and the inconvenience of collection.
A written, personalised prevention plan with a clear daily fluid target.
You collect urine at home over a full day and have blood taken. No discomfort beyond the blood test and the...
Blood and urine results return. Stone analysis can take longer depending on the laboratory.
Your specialist explains the results and agrees a tailored plan — fluid targets, dietary changes and sometimes a...
You build the new habits. Any medicine started is checked for side effects and effect on your urine chemistry.
What is kidney stone prevention and assessment?
Kidney stone prevention and assessment is a set of tests and a specialist review that looks for the reasons you make stones. Most people who have had one stone do not need a deep work-up, but if stones come back, affect both kidneys, start young, or run in your family, finding the cause matters.
The assessment usually looks at what the stone was made of, your blood, and one or two 24-hour urine collections (where you save all your urine for a day). These show things like how much calcium, oxalate, uric acid, citrate and fluid your kidneys are handling. A scan may be used to see whether any stones are still present.
The aim is information and a plan, not a cure. A good assessment tells you your personal risk and which changes are likely to help you specifically — it cannot promise you will never form another stone.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
One stone vs recurrent or high-risk stones
| Single, low-risk stone | Recurrent or high-risk | |
|---|---|---|
| Full metabolic work-up | Often not needed | Recommended |
| 24-hour urine test | Usually not required | Usually advised |
| Preventive medicine | Rarely needed | Considered if tests show a treatable cause |
| Long-term monitoring | Minimal | Periodic scans and tests |
Your specialist decides how far to investigate based on your history, stone type and risk.
Preparing for your test
- Bring any passed stone, or ask whether a removed stone was sent for analysis — this is one of the most useful pieces of information.
- Bring a list of your medicines and supplements; some (including certain calcium, vitamin C and vitamin D products) affect stone risk.
- Note your usual daily drinks and roughly how much you drink, as fluid is central to prevention.
- Follow the 24-hour urine instructions exactly — start with an empty bladder, save every drop for the full period, and keep the container as advised.
- Mention family history of stones, gout, bowel disease or previous kidney problems.
- Tell the team if you are pregnant or might be, as this changes which scans are safe.
- Bring previous scan reports or results if you have them.
What happens
At the clinic, a kidney specialist (nephrologist) or urologist takes a detailed history — how many stones, when, what they were made of, your diet, fluids, medicines and family history. They examine you and arrange blood tests and usually one or two 24-hour urine collections that you do at home.
You collect all your urine over a full day into a special container, then return it to the laboratory. The lab measures the chemicals that drive stone formation. A scan may be arranged to see whether stones remain.
Once results are back, you have a review (in person, by phone or video) where the specialist explains what your results mean and agrees a tailored prevention plan with you. There is no procedure and no recovery — the tests are non-invasive.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- A full metabolic work-up may not be needed after a single, uncomplicated stone in an otherwise low-risk person.
- Assessment alone is not the right step if you have an acute, painful or infected blocked stone — that needs urgent urological treatment first.
- It cannot remove a stone that is already present; it is about preventing future ones.
- It will not help if the real problem is an untreated structural or anatomical issue that needs surgery.
Delay or rearrange if…
- You currently have severe stone pain, fever or a suspected blocked, infected kidney — seek urgent care instead.
- You are pregnant or might be, which affects which scans and some medicines are safe.
- You have a current urine infection, which can distort urine test results.
- You cannot complete an accurate 24-hour urine collection at this time.
Alternatives to discuss
- Simple general advice (drink enough fluid, reduce salt) without a full work-up for low-risk, single stones.
- Watchful waiting with good hydration after a first stone.
- The NHS stone-prevention pathway via your GP or urologist.
- Treating an underlying condition (such as gout or a parathyroid problem) through the relevant specialty.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Identifies treatable causes such as low urine citrate, high urine calcium or high uric acid.
- Lets the team tailor fluid, diet and any medicine to your specific stone type and urine results.
- Can meaningfully reduce how often stones come back when advice is followed.
- Reassures you about what is, and is not, driving your stones.
- Helps plan sensible monitoring so future stones are caught earlier.
Risks & complications
- Inconvenience of collecting urine for a full day and repeating blood tests.
- Results can be normal even though you keep forming stones, which can be frustrating.
- A 24-hour collection done incorrectly (missed urine) can give misleading numbers and may need repeating.
- Incidental findings on a scan that lead to further tests.
- Preventive medicines can have side effects that need monitoring.
- Advice that is hard to stick to long term, so the benefit fades.
- Very rarely, an underlying condition (such as a parathyroid problem) is found that needs its own treatment.
The biggest limitation is that a normal work-up does not mean you will not form more stones, and the benefit of any plan depends on sticking with it. If a scan is used, ask whether a low-radiation option or ultrasound is suitable, especially for repeated monitoring. Ask your specialist which one or two changes matter most for your stone type, so you are not overwhelmed.
Published figures to discuss
Recurrence figures vary a lot depending on how recurrence is defined (any stone seen on a scan versus a painful, confirmed stone) and on the population studied, so treat single numbers with caution. The clearest, most patient-relevant figure is that a substantial minority to around half of people form another stone within a few years, and risk rises with each further stone.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Recurrence after a first stone | Up to about 50% within 5 years | NHS figure for people who have had a kidney stone; this is exactly why prevention is offered. | NHS — Kidney stonesnhs.ukPublished figure |
| Infected obstructed kidney | Emergency | Fever, rigors, sepsis symptoms or uncontrolled pain with suspected stone need urgent hospital assessment. | Guide sourcesClinical context |
| Prevention plan not matched to stone type | Common limitation | Calcium oxalate, uric acid, cystine and infection stones need different dietary, urine and medicine strategies. | NHS — Kidney stonesnhs.ukSource-linked context |
| Radiation exposure from repeated CT scans | Cumulative consideration | Imaging choice should consider pregnancy, age, recurrence and whether ultrasound can answer the question. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no physical recovery. 'Afterwards' is about getting your results and starting a prevention plan you can actually live with.
- Passing more, paler urine once you increase fluids — this is the goal, not a problem.
- Taking time to adjust to drinking more through the day.
- Mild stomach upset when starting some preventive medicines, which often settles.
- No immediate change in how you feel; the benefit is in lowering future risk.
Aftercare
- Drink enough fluid through the day to keep your urine pale — your team will give you a target, often a set volume.
- Follow the dietary advice tailored to your stone type rather than generic 'avoid calcium' rules, which can backfire.
- Take any preventive medicine (such as potassium citrate or a thiazide) as prescribed and attend monitoring tests.
- Cut back on added salt, as high salt raises urine calcium.
- Be cautious with high-dose vitamin C and review supplements with your team.
- Keep a passed stone if you can and report new pain or blood in the urine.
- Attend follow-up tests so the plan can be adjusted if needed.
- Stone saved or sent for analysis
- List of all medicines and supplements
- Note of usual daily fluid intake
- 24-hour urine container collected and instructions read
- Previous scans or results gathered
- Family history of stones noted
- Questions about your stone type written down
⚠ Get urgent help if…
- Severe pain in the side, back, lower tummy or groin that comes in waves.
- Blood in your urine.
- Fever, chills or feeling very unwell with kidney pain — this can mean an infected, blocked kidney and needs urgent care.
- Pain with vomiting that stops you keeping fluids down.
- Difficulty or inability to pass urine.
- Pain with only one kidney, or known poor kidney function, as blockage is more serious.
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good result is a clear picture of why you form stones and a plan that fits your life. For many people the key findings are low urine volume, low citrate, high calcium or high uric acid — all of which can be addressed.
Results cannot prove you will be stone-free. They reduce risk and help catch problems earlier. A normal work-up is reassuring but still means keeping up good fluid intake, because dehydration alone raises risk.
Your stone risk and urine chemistry can change over time with diet, weight, other illnesses and medicines, so a single assessment is a snapshot. Repeat 24-hour urine tests and occasional scans are often used to check the plan is still working, especially if you form another stone or your circumstances change.
Related tests, treatments or support
Stone assessment is often combined with treatment of a stone that is currently present (such as shockwave treatment or a telescopic procedure done by a urologist) and with review of related conditions like gout, high blood pressure or bowel disease that affect stone risk.
Follow-up & long-term care
After the plan is agreed, you are usually reviewed with repeat urine tests to confirm the changes are working, and imaging at intervals to check for new stones. If you start a preventive medicine, blood and urine monitoring is arranged. You should be told who to contact if you pass another stone.
- Keep up your daily fluid target for life — this is the single most important habit.
- Continue tailored dietary changes rather than stopping once stones settle.
- Attend periodic urine tests and scans as advised.
- Have blood and urine monitoring if on a preventive medicine.
- Send any new passed stone for analysis, as stone type can change.
Repeat, follow-on and what comes next
- A 24-hour urine collection that misses urine can give misleading results and may need repeating.
- Tests can be normal even in genuine repeat stone formers, so a normal result does not end the need for good fluid intake.
- Prevention plans often need adjusting over time as urine chemistry, weight or diet change.
- Stone type can change between episodes, so a new stone is worth analysing again.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A written, personalised prevention plan with a clear daily fluid target.
- Dietary advice matched to your stone type, ideally with dietitian input.
- A monitoring schedule (repeat urine tests and appropriate imaging) and blood tests if on medicine.
- A named contact and clear advice on what to do if you pass another stone or develop pain or fever.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Number and length of specialist consultations.
- Which tests are done — blood tests, one or two 24-hour urine collections, and stone analysis.
- Whether imaging is needed, and which type (ultrasound or CT).
- Dietitian input for tailored dietary advice.
- Any preventive medicine and the monitoring tests that go with it.
- Follow-up appointments and repeat testing over time.
- The specialist (nephrologist or urologist) consultation fee.
- Laboratory fees for blood tests, 24-hour urine analysis and stone analysis.
- Any imaging fee and who reports it.
- Whether a dietitian review is included.
- Cost of follow-up appointments and repeat monitoring tests.
- What happens, and what it costs, if results are inconclusive and tests need repeating.
On the NHS? Assessment and prevention of recurrent or high-risk kidney stones is available on the NHS when clinically indicated; private access is often used for a faster appointment, choice of specialist or a second opinion.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Being given generic 'cut out calcium' advice without knowing your stone type, which can backfire for calcium oxalate stones.
- Repeated CT scanning for monitoring without discussing radiation and lower-dose or ultrasound alternatives.
- Starting a preventive medicine without a clear plan for monitoring side effects and effect.
- Expecting the assessment to guarantee no further stones.
Marketing red flags
- Claims that a supplement, cleanse or device will 'dissolve' or 'prevent all' kidney stones.
- Selling a long panel of expensive tests before knowing your stone type or risk.
- Promising a stone-free guarantee.
- Generic plans not tailored to your urine results or stone composition.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- What was my stone made of, and what does that mean for prevention?
- What do my 24-hour urine results show, and which one or two changes matter most for me?
- What fluid target should I aim for each day?
- Do I need a preventive medicine, and what monitoring would that involve?
- How will we check the plan is working, and how often will I be scanned?
- What should I do, and who should I contact, if I pass another stone?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Can I have this assessment on the NHS?
Should I avoid calcium to prevent stones?
How much should I drink?
Why do I need to collect urine for a whole day?
Will the assessment stop me getting stones?
Do I need a scan every time?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NHS — Kidney stones NICE NG118 — Renal and ureteric stones: assessment and management NICE NG118 — Rationale and impact (prevention) BAUS — Kidney stones information Kidney Care UK — Kidney stones
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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