Inflammation of blood vessels, or vasculitis, is caused by a heterogenous group of autoimmune conditions with wide spectrum of systemic, and often overlapping, clinical manifestations. Some of these conditions present acutely and result in major organ's damage and, therefore, require prompt diagnosis and treatment in order to avoid the high morbidity and mortality that otherwise occur. The clinical immunology laboratory plays a vital role in the diagnosis of vasculitis. Moreover, due to the availability of simple tests, with quick turn around time, immunological findings can provide an early picture of the type of vasculitis involved thereby allowing initiation of prompt treatment in life threatening situations. In the present review, we will outline the various tests available in the immunology laboratory for the investigation of vasculitides, discuss the assays used to carry out these tests and, finally, comment on the significance of the results produced in relation to the diagnosis, or exclusion, of vasculitis. We hope that such information would prove of great importance to physicians and immunologists alike and lead to more efficient diagnosis of these important and, often, life threatening conditions.