Gout - Diagnosing gout

The most accurate way to diagnose gout is for your doctor to check your joints for the presence of crystals. However, this test is often not practical to carry out at your local GP practice.

Instead, your GP will first ask about your symptoms and medical history to make a diagnosis.

They will usually ask the following questions:

Which joints are affected?
How quickly did the symptoms appear?
How often do you have symptoms?
Are you taking any medication?
Does anyone in your family have gout?

They will also ask you about your diet, particularly your intake of beer, spirits and foods high in purines, such as red meat and seafood.

Further tests

Many conditions can cause joint pain, inflammation and swelling. Gout is just one of the more than 200 different forms of arthritis (any condition that causes pain and problems with the joints).

Your GP may be unable to make a firm diagnosis straight away and you may be referred for further tests. These will either confirm the diagnosis of gout or rule out other conditions.

Joint fluid

A sample of fluid (synovial fluid) may be taken from the affected joint. This test helps to rule out other crystals (calcium pyrophosphate) that can cause similar attacks of inflammation, as well as an infection in the joint (septic arthritis).

The fluid sample is taken using a needle and examined under a microscope. If you have gout, there will nearly always be crystals of sodium urate in the sample.

Blood test

A type of blood test known as a serum uric acid test may be used to measure the amount of uric acid in your blood.

This test is carried out four to six weeks after an attack of gout, as the serum uric acid level is often not raised at the time of the attack.

However, a serum uric acid test is not definitive. Some healthy people without gout have high uric acid levels in their blood, while others who experience an attack of gout have a normal level.

X-ray

An X-ray is rarely used to diagnose gout because inflammation caused by gout is not usually detectable using this method.

However, an X-ray is sometimes used to help rule out other conditions that affect the joints, such as chondrocalcinosis (a build-up of calcium crystals in the joints).

Ultrasound scan

An ultrasound scan of an affected joint is a simple and safe investigation that is increasingly used to detect urate crystals within the joint cartilage.

It can also detect urate crystals deep in the skin that are not obvious during a physical examination.

Follow-up appointment

About four to six weeks after your gout attack has subsided, your GP may ask you to return for a follow-up appointment to check your serum uric acid level.

Your GP can also give you an advance prescription of painkilling medication so that you can deal with attacks of gout promptly.