Because of its nature, lupus is difficult to diagnose and much will depend on the patient's symptoms. Lupus should be considered in all patients who have
persistent signs of inflammation, including fevers, fatigue and weight loss or manifestations of joint inflammation, skin rash or internal organ problems.
The following tests may be undertaken to arrive at a comprehensive diagnosis:
- Anti-nuclear antibody (ANA) test. About 95% of people with lupus are ANA positive. This test can also be positive in some healthy people;
- Anti-DNA antibody test. If people are positive in this test and the ANA then a diagnosis of lupus is virtually certain. The test results usually go up
when lupus becomes more active, doctors use this measure to see whether the patient is experiencig a flare up or not;
- Anti-Ro antibody test. A positive result in this test indicates that people may be more likely to get skin rashes. Pregnant women with anti-Ro
antibodies will have a 2% chance that their babies will have neonatal lupus syndrome;
- Antiphospholipid antibody test. A positive result for these antibodies means that the patient is at increased risk of miscarriage and also of
developing blood clots;
- Complement level tests. These measure a set of proteins in the blood. The complement levels tend to go down when lupus is more active. The main complement
tests used in diagnosing lupus are known as C3 and C4;
- Kidney and liver function tests. These are done to see if the liver or kidneys are affected. Regular tests are taken to see if there are problems;
- Blood cell counts. These are taken to see if the bone marrow is affected.
If it is suspected that other organs may be affected further tests may be carried out using x-rays, ultrasound scans, computerised tomography or
MRI scans.
