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

The anti-nuclear antibody (ANA) test has the highest sensitivity for systemic lupus erythematosus (SLE). In SLE, the presence of autoantibodies is a hallmark feature, and the ANA test detects a wide range of these antibodies found in various autoimmune conditions.

Although a positive ANA is not specific to SLE, it is indeed very sensitive. Approximately 95% of patients with SLE will have a positive ANA test result, which means that if a patient has lupus, the likelihood that they will test positive for ANA is very high. This makes it an essential initial screening tool when SLE is suspected.

The other antibodies listed, such as anti-double stranded DNA, anti-Smith, and anti-Ro antibodies, have greater specificity for SLE but lower sensitivity. For example, anti-double stranded DNA antibodies are highly specific for SLE and can indicate disease activity but are found in only about 60-70% of patients with SLE. Anti-Smith antibodies are similarly specific but occur in an even smaller percentage of patients (around 20-30%). Anti-Ro antibodies can be associated with SLE but are also found in other conditions, with sensitivity that does not surpass that of the ANA test.