Indications: The ANA test is most commonly used in the diagnosis of SLE. It is almost 100% sensitive because virtually all patients with SLE have a positive ANA result. However, ANAs are not specific at all because they may be seen in other connective tissue diseases such as drug-induced lupus (>95% of patients are ANA positive), scleroderma (70%–90%), inflammatory myositis (40%–60%), and Sjögren’s syndrome (75%–90%). Moreover, even some healthy persons have positive ANA results, particularly at low titer. The ANA test should not be used to screen patients with joint pain or presumed systemic illness.