How Is Gout Diagnosed?
Tests, Scans and What to Expect
Diagnosing gout isn't just one blood test. Here's how doctors actually confirm it — from your history and a joint examination, through urate testing and joint fluid analysis, to ruling out other causes — based on current NICE guidance.
Doctors diagnose gout by combining your history and a joint examination with a blood test for uric acid (urate), and, where the diagnosis isn't clear, by examining fluid taken from the joint for urate crystals — the most definitive test available. Imaging is sometimes used too. A single normal blood test doesn't rule gout out, especially if it's taken during a flare.
How Doctors Approach a Suspected Gout Diagnosis
Before anything is confirmed, a doctor typically builds a picture rather than relying on any single sign. NICE guidance recommends suspecting gout when someone has rapid onset — often overnight — of severe pain together with redness and swelling, in one or both of the joints at the base of the big toe, or where there are tophi. The same pattern in the ankle, knee, hand or another joint is also grounds to consider gout, even though the big toe is the classic site.
This starts with your history: how the symptoms began, which joint is affected, whether you've had similar episodes before, and any relevant medicines or health conditions. It's followed by an examination of the joint itself. NICE guidance is explicit that before gout is confirmed, a doctor should assess the possibility of septic arthritis, calcium pyrophosphate crystal deposition (pseudogout) and other inflammatory arthritis in anyone presenting with a painful, red, swollen joint — because these can look very similar in the early stages.
Serum Urate Testing
A blood test to measure serum urate (uric acid) is a standard part of diagnosing gout. Under NICE guidance, a serum urate level of 360 micromol per litre or above supports the diagnosis. This is the same target level used for monitoring treatment, which our guides to uric acid levels and uric acid and gout cover in more detail.
In practice, it's a simple blood draw from a vein in your arm, usually done alongside other routine bloods, and doesn't require fasting beforehand. In the UK, results typically come back from the lab within a few days rather than immediately. On its own, though, a blood test is only one piece of the picture, not a full diagnosis by itself — which is exactly why it's interpreted alongside your history and examination, not in isolation.
Why Urate Can Be Misleading During a Flare
Here's a complication worth knowing about: uric acid levels can fall during an acute gout flare, sometimes to within a "normal" range, even in someone who does have gout. This happens because the inflammatory response of an attack can temporarily change how urate is handled in the body, including how much is cleared through the kidneys — a well-recognised pattern in clinical practice, even though the exact mechanism isn't fully settled. The effect is usually temporary, and levels tend to move back toward their true baseline once the flare has resolved.
A single normal result taken while your joint is actively flaring doesn't reliably rule gout out. It's exactly why doctors don't rely on one blood test in isolation, particularly for a first episode.
Repeat Testing When the First Result Isn't Clear
If your serum urate comes back below 360 micromol/litre during a flare but gout is still strongly suspected, NICE guidance recommends repeating the test at least 2 weeks after the flare has settled, once the temporary drop caused by the attack itself has passed. A result taken between attacks gives a clearer picture of your baseline level than one taken during the flare itself.
This baseline reading matters beyond diagnosis too: if gout is confirmed and you and your doctor decide on long-term urate-lowering treatment, the same 360 micromol/litre threshold becomes the target your treatment aims to get you below and keep you under, so an accurate starting point is genuinely useful.
Joint Aspiration and Synovial Fluid Analysis
Where the diagnosis isn't clear from history, examination and blood tests alone, NICE guidance recommends joint aspiration and microscopy of synovial fluid — taking a small sample of fluid from the affected joint with a fine needle and examining it under a polarised light microscope for urate crystals. Finding these crystals is the most definitive way to confirm gout, and the same sample can also be tested to help rule out infection.
This is more likely to be recommended for a first episode without a clear diagnosis, when the presentation is atypical, or when it's important to rule out joint infection rather than assume gout. It's usually done by a GP with the right training or in a rheumatology clinic, using local anaesthetic, and most people find it uncomfortable rather than acutely painful.
Ruling Out Septic Arthritis and Pseudogout
Several conditions can produce a sudden, hot, swollen joint that looks very similar to gout, which is why ruling them out matters as much as confirming gout itself.
Septic arthritis — a bacterial infection inside the joint — is the most urgent possibility to exclude, since it's a medical emergency requiring immediate treatment. If it's suspected, NICE guidance calls for immediate referral rather than waiting for routine test results.
Calcium pyrophosphate crystal deposition, or pseudogout, is caused by a different type of crystal and can look almost identical to gout on examination alone; the two are usually only reliably told apart by testing. For the full comparison, see our guide to gout vs pseudogout. Reactive arthritis, other forms of inflammatory arthritis, and simple joint injury are also part of the picture a doctor considers before settling on a gout diagnosis, particularly in a younger person or where the pattern doesn't quite fit.
Imaging: Ultrasound, X-ray and Other Scans
When aspiration isn't possible, or the diagnosis is still unclear afterwards, NICE guidance suggests considering imaging — X-ray, ultrasound, or dual-energy CT — of the affected joint.
Ultrasound can pick up signs of urate deposits on the joint surface and can also help guide aspiration in a difficult joint. X-ray is less useful for a first, early attack, but can show joint damage typical of longer-standing, poorly controlled gout. Dual-energy CT is a more specialised scan that can directly visualise urate deposits, and tends to be used selectively rather than routinely. None of these scans replace crystal identification as the definitive test — they support the diagnosis rather than confirming it outright.
Can You Have Gout With Normal Uric Acid?
Yes. As covered above, uric acid can genuinely sit within the normal range during an acute flare, so a single normal result doesn't rule gout out, particularly if it was taken while your joint was actively inflamed. It's also possible to have a confirmed gout diagnosis and a normal or even low urate reading between attacks, especially once treatment has started to lower it.
This is exactly why crystal identification from joint fluid, not the blood test alone, is considered the definitive way to confirm gout. For a deeper look at how uric acid levels relate to symptoms and diagnosis, see our guide to uric acid and gout.
What Happens After Diagnosis?
Once gout is confirmed, treatment usually has two separate strands: managing the current flare, and deciding whether ongoing treatment is needed to lower uric acid long term. A flare is typically treated with anti-inflammatory medication or steroids, alongside rest and self-care — see our guide to gout treatment.
Longer term, NICE guidance supports offering urate-lowering therapy to people with recurrent flares, tophi, chronic kidney disease, or gout affecting multiple joints, among other factors — your doctor will talk you through whether this applies to you. If you're having repeated attacks, our guide to recurrent gout explains why they happen and what ongoing management can involve.
Most people are also reviewed periodically afterwards, with follow-up urate checks used to see whether treatment (if started) is working, alongside general conversations about weight, alcohol and other everyday factors that can influence future attacks.
When to Seek Urgent Medical Help
You have a painful, hot, swollen joint together with a fever or feeling generally unwell or shivery; the pain and swelling are rapidly getting worse; you're unable to move or bear any weight on the joint; or this is your first time experiencing symptoms like this and you don't already have a gout diagnosis. These can be signs of joint infection, which needs prompt treatment. Fever alongside a hot, swollen joint deserves attention in its own right — see our guide to gout and fever for more. In the UK, this generally means contacting your GP practice for a same-day appointment, calling NHS 111 for urgent advice outside GP hours, or attending A&E if you feel very unwell.
Frequently Asked Questions
How is gout officially diagnosed?
Through a combination of your history, a joint examination, a blood test for uric acid, and — where the diagnosis isn't clear — examining joint fluid for urate crystals, which is the most definitive test.
Can a blood test alone diagnose gout?
Not reliably on its own. Uric acid can be misleadingly normal during a flare, and some people without gout have raised uric acid without ever developing symptoms, so blood results are interpreted alongside your history and examination.
What is the gold standard test for gout?
Examining synovial fluid taken from the joint under a polarised light microscope for urate crystals is generally considered the most definitive way to confirm gout.
Does a normal uric acid level rule out gout?
No. Uric acid can drop during an acute flare, so a normal result taken at that time doesn't reliably rule gout out.
Is joint aspiration painful?
Most people describe it as uncomfortable rather than severely painful, and it's usually done under local anaesthetic. It only takes a few minutes.
How quickly can gout be diagnosed?
Often within one appointment if symptoms are typical and a blood test supports it, though confirming an unclear case with joint fluid analysis or imaging can take longer.
Can gout be misdiagnosed as something else?
Yes — gout can be mistaken for joint infection, pseudogout, or other types of arthritis, which is exactly why ruling these out is part of a proper diagnosis.
Should I see a doctor before assuming I have gout?
Yes. A first episode of joint pain and swelling should always be properly assessed, both to confirm gout and to rule out other causes, including joint infection where urgent care is needed.
Related Reading
Gout Symptoms
What a gout attack feels and looks like, and when to get help.
Read guide →Uric Acid and Gout
How uric acid relates to symptoms, testing and treatment targets.
Read guide →Gout vs Pseudogout
How these two very similar-looking conditions are told apart.
Read guide →Gout Treatment
Treating a flare and managing the underlying cause long term.
Read guide →This guide is for general educational purposes and explains how gout is typically diagnosed — it is not personal medical advice and cannot confirm whether your own symptoms are gout. Never start, stop or change a medicine based on this page. Always speak with your own doctor, and seek urgent care for the warning signs described above.