Investigations in Rheumatology Series- 7 ANCA – Methods, Techniques & its role in Rheumatology


Dr. Renuka spoke about the ANCA testing methods and technology like Indirect Immunofluorescence (IIF), Antigen-specific ELISA, and chemiluminescent immunoassay (CLIA) and other new emerging technology. ANCA should be tested only if there is a clinical indication and should not be used as a general screening test for autoimmunity. IIF is the method of choice for ANCA testing in the diagnosis of IBD, autoimmune hepatitis or drug-induced vasculitis as a wider array of antigens may be present and may therefore be more convenient.

Dr. Aman Sharma discussed the importance and criteria of ANCA testing in AAV- Granulomatosis with polyangiitis (GPA), Microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). PR3 and MPO are the targets of C-ANCA and p-ANCA respectively in small vessel vasculitis. ANCA testing should be advised when there is clinical suspicion of systemic vasculitis. Immunoassay is a better method over IIF for ANCA testing in GPA and MPA.