Clinical use of serological tests for antineutrophil cytoplasmic antibodies. What do the studies say?

Trustworthy and clinically useful laboratory test results depend on high quality laboratory knowledge and performance and on close collaboration with experienced clinicians. Just like a diagnosis can only be made by contrasting it to a number of differential diagnoses, a prototype autoantibody profile can only be recognized if autoantibodies that partially mimic the former are just as well-known. In antineutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitides the characteristic autoantibody profile can only be demonstrated by use of at least two different methodologies and an assay-specific cut-off selection that clearly distinguishes between strongly positive and disease control low positive to negative values. Local serum banks containing samples from patients with well-characterized chronic immunoinflammatory diseases and ANCA-associated vasculitides are needed for such important studies whether in-house or commercial assays are used.