THE ANCA TEST - ITS CLINICAL RELEVANCE

In theory, the diagnosis of vasculitis depends on the presence of certain clinical features and the demonstration of vascular disease by either biopsy or angiography.' In practice, there have been many difficulties in formulating a satisfactory classification of the vasculitides. In Wegener's granulomatosis, for example, where there are prominent pulmonary changes, infections, other granulomatous conditions, and neoplastic diseases may produce a similar clinical picture, and biopsy specimens are often nondiagnostic. 2 The demonstration that antineutrophil cytoplasmic antibodies (ANCAs) are present in most cases of Wegener's granulomatosis has provided a useful diagnostic tool and may shed light on the pathogenesis of vasculitis.