About Antinuclear Antibodies Screen
The ANA (Antinuclear Antibody) screen detects whether the immune system is producing antibodies against components of the cell nucleus — the defining feature of most systemic autoimmune diseases. A positive ANA is found in lupus, Sjögren's syndrome, scleroderma, and mixed connective tissue disease, but also in up to 20% of healthy people (especially women) with no disease. A positive result requires follow-up with specific antibody subtests (anti-dsDNA, anti-Sm, anti-SSA/SSB) to identify the underlying condition.