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SSB (La) antibody is seen in 50-60% of Sjögren syndrome cases and is specific if it is the only ENA antibody present. Autoantibodies directed against Ro/SSA and La/SSB autoantigens were originally identified in patients with Sjögren’s syndrome and systemic lupus erythematosus (SLE). 15-25% of patients with systemic lupus erythematosus (SLE) and 5-10% of patients with progressive systemic sclerosis (PSS) also have this antibody. SSA and SSB are both extractable nuclear antigens (ENA) that are useful markers for these autoimmune diseases. In addition to being found in some patients with Sjogren’s syndrome and LE, SSA antibody can also be seen in patients with rheumatoid arthritis and in infants with neonatal LE. It is important to note that testing for SSA and SSB antibodies is not of use for patients who do not have demonstrable antinuclear antibodies (ANA-negative patients).