Systemic lupus erythematosus (SLE) can be a difficult condition to diagnose. This is because the symptoms of SLE are sometimes very similar to a number of other conditions, most of which are far more common than SLE.
SLE may also be difficult to diagnose because the symptoms can vary greatly from person to person. Your symptoms may also change over time. For example, there may be periods where your symptoms are not very noticeable, or times when they ‘flare-up’ and become more severe.
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If your GP suspects that you may have SLE after examining your symptoms, they will need to refer you for a series of blood tests in order to help confirm the diagnosis.
Some of the blood tests that may be carried out are listed below.
Anti-nuclear antibody test
An anti-nuclear antibody test checks to see whether there is a certain type of antibody cell in your blood, known as the anti-nuclear antibody. Approximately 95% of people with SLE have this antibody.
However, it is possible to have the anti-nuclear antibody without having SLE, so the anti-nuclear antibody test is not a definitive way of testing for the condition. Your GP will need to use other tests in order to help confirm the diagnosis.
Anti-DNA antibody test
An anti-DNA tests also checks for a certain type of antibody in your blood. If you have the anti-DNA antibody, it is highly likely you will have SLE. But again, the antibody can also be present in people who do not have the condition.
The level of anti-DNA antibodies increases when SLE is more active, so during a flare-up of symptoms your reading from this test may be greater than normal.
Completement level test
Completement is a chemical in the blood which forms part of your immune system. Your GP may test the level of this chemical in your blood in order to check how active your SLE is. The level of completement in your blood decreases when SLE is more active.
Once you have been diagnosed with SLE, you will normally need to undergo regular check-ups and tests to monitor how the condition is affecting your body.
If you have SLE it is possible that you may go on to develop other conditions, such as anaemia or kidney problems. Monitoring your condition will allow your doctor to check for these secondary conditions and, if necessary, provide treatment for them as soon as possible.
You may need to undergo a scan, such as an X-ray, ultrasound scan or a computerised tomography (CT) scan in order to check whether SLE is affecting your internal organs.