Anti Neutrophil Cytoplasmic Antibody ANCA Test

Anti neutrophil cytoplasmic antibody (ANCA) tests are used to diagnose and monitor inflammatory activity in the primary systemic small vessel vasculatures. It is most often used to find out if you have a type of autoimmune vasculitis like Wegener granulomatosis, microscopic polyangiitis and its renal-limited variant (pauciimmune crescentic glomerulonephritis), and Churg-Strauss syndrome.

The test measures the presence or absence of specific anti neutrophil cytoplasmic antibodies in the blood.

This test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer.

• c-ANCA is associated with Wegener's granulomatosis and less frequently with microscopic polyangitis.Approximately 85% of patients with a C-ANCA pattern by IFA have antibodies specific for PR3.
• p-ANCA is associated with microscopic polyangiitis and focal necrotizing and crescentic glomerulonephritis.
• Churg-Strauss syndrome is associated with p-ANCA directed against MPO. Approximately 90% of patients with a P-ANCA pattern by IFA have antibodies specific for MPO. Atypical P-ANCA is described with a mixed group of inflammatory diseases e.g sclerosing cholangitis and connective tissue disorders. Antigen targets include lactoferrin,elastase,cathepsin G and BPI.
• Patients with a number of other diseases, such as ulcerative colitis and ankylosing spondylitis, will commonly have ANCA as well.