Test Background Commonly positive at high titre (>1:640) in patients with SLE and other connective tissue diseases. The presence of ANA is indicative of SLE (present in 80-90 % of cases) although they also appear in some other autoimmune diseases, such as Sjögren’s syndrome (60 %), rheumatoid arthritis, autoimmune hepatitis, scleroderma and poly/dermatomyositis, Hashimoto’s disease and autoimmune haemolytic anaemia. Weak positive reactions are not uncommon and may have no clinical significance.
Clinical Indications ANA should be requested for investigations of suspected connective tissue autoimmune syndromes. Autoantibody screening should be reserved for investigations where there is suspected liver involvement and/or anaemia. Autoimmune symptoms are typically variable and include:
painful or swollen joints