Antinuclear antibody screen
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.
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 unexplained fever back pain extreme fatigue rashes
|Sample & container required||RST (rust top)|
|Sample volume||5-10 mL (1 mL serum)|
|Turnaround time||4 days|
This test is currently unaccredited due to a recent change in platform.