Dementia diagnosis (Diagnostic assessment for suspected dementia)
The process of finding out whether memory and thinking problems are due to dementia, what type it might be, and ruling out other causes, so that support and planning can begin.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- Dementia is diagnosed from the whole picture – history, memory tests, blood tests and sometimes a scan – not a single test.
- A diagnosis is not a cure; most types of dementia cannot be reversed, but a diagnosis opens the door to support, planning and treatments that may help.
- Other treatable conditions can mimic dementia, so part of the assessment is ruling these out.
- Getting a diagnosis can take from a few weeks to much longer; it allows you and your family to plan while you are best able to.
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.
Explains what is causing the changes, rather than leaving you uncertain
A sudden change in confusion or alertness over hours or days, which needs urgent medical assessment for causes such as infection or stroke, not a routine...
Your symptoms are reviewed, a brief memory test is done, and blood tests are arranged to exclude other causes. You may be referred on if dementia remains...
An accurate diagnosis explained with care, including the type and how confident the team is.
Your symptoms are reviewed, a brief memory test is done, and blood tests are arranged to exclude other causes. You...
A memory service or specialist takes a fuller history and does more detailed tests. This may be one visit or...
A CT or MRI scan may be arranged and reported separately. Not everyone needs a scan, and a normal scan does not...
The team brings everything together and explains the diagnosis, the type if known, and what it means. This should...
What is involved in diagnosing dementia?
Diagnosing dementia is a process rather than a single test. There is no one test that says yes or no. Instead, a GP and then a specialist team build up a picture from several things: a detailed account of the changes, often with help from someone close to you; tests of memory and thinking; blood tests; and sometimes a brain scan. The aim is to find out whether the difficulties are caused by dementia, what type it might be, and to rule out other, sometimes treatable, causes.
Many things can mimic dementia, including depression, anxiety, thyroid problems, vitamin deficiencies, infections, poor sleep, alcohol and side effects of medicines. Part of the value of a proper assessment is finding and treating these, because they can sometimes explain the symptoms entirely.
It is important to be honest about what a diagnosis can and cannot do. A diagnosis is not a cure. There is no treatment that reverses most types of dementia. What a diagnosis can do is explain what is happening, open the door to treatments that may help symptoms or slow some types, connect you with support, and allow you and your family to plan ahead while you are best able to. For some people, the most important outcome is finding a treatable cause instead.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
What different parts of the assessment can and cannot do
| Part | What it shows | What it cannot do |
|---|---|---|
| Memory tests | How memory and thinking are working now | Diagnose dementia on their own |
| Blood tests | Treatable causes that mimic dementia | Confirm dementia |
| Brain scan | Shrinkage, stroke, the likely type | Rule dementia in or out alone |
| History from family | Changes over time | Replace medical tests |
No single part is enough by itself. A diagnosis comes from putting them together, and a normal scan does not mean someone does not have dementia.
Preparing for your test
- Bring someone who knows you well, as their account of changes over time is one of the most useful parts of the assessment.
- Make a note of when problems started, how they have changed, and examples from daily life.
- Bring a full list of your medicines and supplements, as some affect memory and thinking.
- Mention mood, anxiety, sleep, alcohol and recent illnesses, which can all affect memory.
- Bring your glasses and hearing aids if you use them, so tests are fair.
- Gather any previous letters, results or scans that might be relevant.
- Write down your questions, including what a diagnosis would change and what support is available.
What happens
The process usually starts with your GP, who asks about your symptoms and general health, does a short memory test, examines you, and arranges blood and sometimes urine tests to look for other causes. If possible, someone who knows you well comes too, to describe any changes they have noticed.
If dementia remains a possibility, you are referred to a memory service or a specialist – often a psychiatrist, geriatrician or neurologist – who takes a fuller history and carries out more detailed memory and thinking tests. A brain scan, usually a CT or MRI, may be arranged where it would help to look for shrinkage, stroke damage or other changes and to suggest the type of dementia.
The specialist then brings everything together – the history, the test scores, the blood results and any scan – to reach a diagnosis. Most cases can be diagnosed after these assessments, although sometimes the picture is unclear and a period of review is needed. When a diagnosis is given, the specialist should explain what it means, what type it is if known, what treatments and support are available, and help you start to plan ahead.
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 sudden change in confusion or alertness over hours or days, which needs urgent medical assessment for causes such as infection or stroke, not a routine memory pathway.
- As a quick, single-visit label, since an accurate diagnosis needs the whole picture and sometimes review over time.
- When a clearly treatable cause, such as severe depression or a thyroid problem, has not yet been addressed.
- As a screening test in someone with no symptoms, where it can cause harm without clear benefit.
Delay or rearrange if…
- There is an acute illness, infection or delirium, which can mimic dementia and should be treated first.
- Severe depression, anxiety or another treatable condition is likely to be driving the symptoms.
- A recent medicine change is affecting thinking and the picture may settle.
- The person is too unwell, distressed or exhausted for a fair assessment on the day.
Alternatives to discuss
- Assessment and exclusion of treatable causes by a GP before specialist referral.
- Treating depression, poor sleep, alcohol or medicine effects and then reassessing.
- A period of monitored review if the picture is unclear and symptoms are mild.
- Referral to a memory service or specialist for a fuller opinion.
- Support and information for the person and family while the situation is monitored.
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
- Explains what is causing the changes, rather than leaving you uncertain
- Rules out treatable conditions that can mimic dementia
- Opens access to treatments that may help symptoms or slow some types
- Connects you and your family with support, advice and services
- Allows planning ahead – legal, financial and care decisions – while you are best able to
- Helps family and carers understand what is happening and what to expect
Risks & complications
- The process can be stressful and emotional for you and your family
- It can take several appointments and weeks before there is a clear answer
- Test scores can be affected by mood, anxiety, tiredness, education and language
- Waiting for blood tests or a scan before anything is confirmed
- An unclear picture that needs review over months rather than a quick diagnosis
- Difficulty being certain of the exact type of dementia
- An incidental finding on a scan that leads to further tests
- A wrong or premature label, which is why the whole picture and sometimes review are needed
- Missing a treatable cause if the assessment is rushed or incomplete
The assessment itself is talking, testing and sometimes a scan, so it carries little physical risk. The real risks are about getting the diagnosis right and handling it well: a label given too quickly, a treatable cause missed, or a diagnosis delivered without support and a plan. Ask what the diagnosis is based on, how confident the team is about the type, and what support and follow-up come with it.
Published figures to discuss
Diagnosing dementia is about reaching the right conclusion from several pieces of information, so the key uncertainties are about accuracy and type rather than physical complications. No single test is definitive: memory tests, blood tests and scans each have limits, and a normal scan does not rule dementia out. Confidence in the exact type is often lower than confidence that a problem exists, and reliable, defensible accuracy figures for the overall diagnosis in routine practice are limited, so we describe the uncertainty qualitatively rather than quoting a single rate.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| No single definitive test | Core diagnostic limitation | Memory tests, blood tests, scans and collateral history are combined; one normal result does not exclude dementia. | Guide sourcesClinical context |
| Potentially reversible contributors | Recognised | Delirium, depression, sleep apnoea, medicines, alcohol, thyroid disease, B12 deficiency and sensory impairment should be considered. | Guide sourcesClinical context |
| Subtype uncertainty | Common early in disease | Alzheimer's, vascular, Lewy body and frontotemporal patterns can overlap and may become clearer over time. | Guide sourcesClinical context |
| Driving, capacity and safeguarding implications | Clinically important | Diagnosis should include practical advice on notifying the driving licence authority (the DVLA in England, Scotland and Wales; the DVA in Northern Ireland), finances, medicines, falls, fire risk and future planning. | NHS – How to get a dementia diagnosisnhs.ukSource-linked 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 nothing to recover from physically. What matters afterwards is understanding the diagnosis, knowing what it means for you and your family, and being connected to treatment, support and a plan for the future.
- No physical after-effects from the assessment
- Strong emotions – shock, relief, grief or fear – which are a normal reaction
- Needing time and more than one conversation to take in a diagnosis
- Waiting weeks, occasionally longer, for the picture to become clear
- Being offered follow-up, support and review rather than being left alone with it
Aftercare
- Make sure you understand the diagnosis, the type if known, and what it is based on.
- Ask what treatments are available, what they can realistically do, and their side effects.
- Ask to be connected with support services, such as a dementia adviser or local groups.
- Plan ahead while you are able – consider Lasting Power of Attorney and advance wishes.
- Check what the diagnosis means for driving and work, and what you must tell the driving licence authority - the DVLA if you live in England, Scotland or Wales, or the DVA if you live in Northern Ireland.
- Make sure family or carers are included and supported, with their own questions answered.
- Know who to contact between appointments and what would count as urgent.
- Someone who knows you well to attend appointments with you
- A clear record of when symptoms started and how they have changed
- An up-to-date list of medicines and supplements
- Any previous letters, results or scans
- Your glasses and hearing aids if you use them
- A written list of questions, including about support and planning
- Knowing how and when you will get results and who to contact
⚠ Get urgent help if…
- A sudden change in confusion, alertness or behaviour over hours or days – seek urgent help
- Confusion with fever, a severe headache, or feeling very unwell
- New weakness, numbness, slurred speech or difficulty walking – call 999 for possible stroke
- A sudden fall or injury, especially with a knock to the head
- Distress, agitation or risk that you or carers cannot manage safely
- Thoughts of self-harm, or being unable to keep safe – seek help now
- Any symptom your clinician told you to treat as urgent
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 clear result is an honest explanation of whether the symptoms are due to dementia, what type it is if that can be told, and what has been ruled out. For some people the most important outcome is finding a treatable cause instead. The diagnosis comes from the whole picture, and the team should say how confident they are, since the exact type is not always certain.
It is important to be clear about what a diagnosis cannot do. It is not a cure, and for most types there is no treatment that reverses the condition. What it can do is explain what is happening, guide treatments that may help symptoms or slow some types, and open access to support and the chance to plan ahead. A good diagnosis is one that is accurate, explained with care, and followed by support – not just a label.
A dementia diagnosis is the beginning of an ongoing relationship with services, not a one-off event. Dementia changes over time, so the plan, treatments and support are reviewed as needs change. If the diagnosis or type was uncertain, it may be revisited as things become clearer. Planning made early – about care, finances and wishes – remains valuable as the condition progresses.
Related tests, treatments or support
Diagnosing dementia builds on a memory and cognitive assessment, blood tests and sometimes a brain scan. It often sits alongside treating other conditions such as depression, and managing general health. After diagnosis, it connects with treatments, support services, carer support, and planning tools such as Lasting Power of Attorney, which work best when started early.
Follow-up & long-term care
After a diagnosis, you should be connected with treatment options and support, and offered follow-up to review symptoms, treatments and needs over time. Regular reviews, often shared between your GP and the specialist team, allow the plan to change as the condition does. You should be told who to contact between appointments and what counts as urgent.
- Regular reviews of symptoms, treatments and care needs as they change
- Ongoing support for family and carers, including their own wellbeing
- Keeping plans up to date – Lasting Power of Attorney, advance wishes and finances
- Managing other health conditions, which can affect symptoms
- Reviewing driving and other safety issues over time
Repeat, follow-on and what comes next
- A diagnosis or its type may be revised as the condition evolves or more information comes in.
- Some people need review over months before the picture is clear enough to be confident.
- A treatable cause found later can change the diagnosis entirely.
- Plans and treatments are adjusted over time as needs change, rather than fixed at diagnosis.
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
- An accurate diagnosis explained with care, including the type and how confident the team is.
- Clear information on treatments, what they can realistically do, and their side effects.
- Connection to support services for the person and their family or carers.
- Help with planning ahead and a named contact, with ongoing review as needs change.
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:
- How many appointments are needed to reach a diagnosis
- Who is involved (GP, psychiatrist, geriatrician or neurologist)
- The depth of cognitive testing used
- Blood tests to exclude other causes, charged separately
- Whether a brain scan is needed and who reports it
- Follow-up appointments and ongoing review
- Reports or letters requested for legal, financial or care purposes
- The specialist's fees and how many appointments are likely
- Whether cognitive testing and a written report are included
- Whether blood tests are included or charged separately
- The cost of a brain scan if needed, including reporting
- What follow-up and ongoing review are included, and their cost
- What happens, and what it costs, if the diagnosis is unclear and review is needed
- The cancellation policy
On the NHS? Dementia diagnosis is available on the NHS through GPs and memory services when clinically indicated; private assessment may be used for speed or choice, but ongoing NHS support is usually still needed.
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
- Giving a diagnosis quickly without explaining what it is based on or how certain the type is.
- Not ruling out treatable causes before reaching a conclusion.
- Delivering a diagnosis without support, follow-up or a plan.
- Not involving the person and family in what the diagnosis means and what happens next.
- Not being honest that a diagnosis is not a cure for most types of dementia.
Marketing red flags
- Offering a single scan or blood test as a way to 'diagnose dementia' in isolation.
- Promising early diagnosis as if it changes the outlook for most types of dementia.
- Selling assessments without the support, follow-up and planning that should come with a diagnosis.
- Implying treatments can reverse dementia.
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 is the diagnosis based on, and how confident are you about the type?
- What treatable causes have been ruled out?
- What treatments are available, and what can they realistically do?
- What support is there for me and for my family or carers?
- What should I do about driving, work and telling the driving licence authority (the DVLA in England, Scotland and Wales, or the DVA in Northern Ireland)?
- How will my care be reviewed over time, and who do I contact between appointments?
- 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
Is there a single test for dementia?
Will a diagnosis cure or reverse it?
Why bother getting a diagnosis if there is no cure?
How long does it take to get a diagnosis?
Could it be something other than dementia?
Can I get a diagnosis privately?
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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 – How to get a dementia diagnosis NHS – Tests for diagnosing dementia Alzheimer's Society – How to get a dementia diagnosis Alzheimer's Society – Tests and scans to diagnose dementia NHS England – Dementia diagnosis and management (primary care resource) DVLA — assessing fitness to drive (Great Britain) DVA Northern Ireland — telling DVA about a medical condition
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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