Antinuclear antibody (ANA) testing in primary care. The test is positive what now? A two-phase observational study of UK primary care.

Defining the test result is difficult. However, there is clear differentiation between the positive and negative/unknown cohorts. Positive-test status is associated with ANA-disease development and mortality. If ANA-positive, most of those who will develop disease are diagnosed soon after testing; male gender and advanced-age reduce the risk of ANA-diseases.