See a GP if you have symptoms of Sjögren's syndrome.

They'll ask about your symptoms and look at your eyes and mouth to check for any obvious problems.

Because there are many conditions with similar symptoms to Sjögren's syndrome, it can be very difficult for a GP to diagnose.

They can refer you to a specialist for further checks, if needed.

Blood tests can be done to look for antibodies in your blood. Antibodies are substances produced by your immune system (the body's defence against infection) to attack germs.

In Sjögren's syndrome, the immune system produces antibodies that attack healthy areas of the body. These can be found during a blood test.

But not everyone with Sjögren's syndrome has these antibodies, so you may have the condition even if a blood test does not find them.

An eye doctor (ophthalmologist) may do a test to look at the layer of tears that forms across the front of your eyes.

Harmless coloured drops are put in your eyes to make the layer of tears easier to see for a short time. A special microscope with a light is then used to look at your eyes.

If the layer of tears is very patchy, it could be a sign of Sjögren's syndrome.

In people with Sjögren's syndrome, clumps of white blood cells, which are produced by the immune system, can form inside the cells where spit (saliva) is produced.

To check for this, a very small piece of tissue from the inside of your lip may be removed and looked at under a microscope. This is known as a lip biopsy.

Local anaesthetic is injected into your lip to numb it before the procedure.

Occasionally, other tests may be done. These may include:

• a spit test – you spit as much saliva as you can into a cup over a 5-minute period and the amount is then measured or weighed
• measuring how many tears you produce – small strips of paper are placed in your lower eyelid for 5 minutes to see how much of the paper is soaked with tears

Producing less saliva or fewer tears than normal can be a sign of Sjögren's syndrome.