What lab test has the highest sensitivity for systemic lupus erythematosus (SLE)?

The anti-nuclear antibody (ANA) test is recognized for its high sensitivity in detecting systemic lupus erythematosus (SLE). It is a screening test that can identify a wide range of autoimmune disorders, with SLE being one of the most commonly associated conditions. Approximately 95% of patients with SLE will test positive for ANA, which makes it a valuable initial test in the evaluation of suspected lupus.

Though other tests like anti-double stranded DNA antibodies have higher specificity for SLE, they do not have the same sensitivity as ANA. A complete blood count is useful for assessing related hematological abnormalities but does not serve as a primary diagnostic tool for SLE. Serum complement levels can indicate disease activity but are not utilized primarily for diagnosis.

Thus, the high sensitivity of the ANA test makes it the most appropriate choice for initial screening in suspected cases of systemic lupus erythematosus.