MPO-ANCA(P-ANCA Detail

The MPO-ANCA (P-ANCA) Test is a blood test that measures the presence of antineutrophil cytoplasmic antibodies (ANCA) directed against myeloperoxidase (MPO), an enzyme found in certain white blood cells. These antibodies are associated with a group of autoimmune diseases known as ANCA-associated vasculitis (AAV), which involves inflammation and damage to small and medium-sized blood vessels.

The test is referred to as P-ANCA because of the perinuclear staining pattern seen under immunofluorescence microscopy when MPO antibodies bind to neutrophils.

This test is most commonly used to support the diagnosis of:

• Microscopic Polyangiitis (MPA)

• Eosinophilic Granulomatosis with Polyangiitis (EGPA, formerly Churg-Strauss Syndrome)

• Sometimes seen in Systemic Lupus Erythematosus (SLE) or Ulcerative Colitis

It is often performed alongside PR3-ANCA (C-ANCA) to differentiate between different types of vasculitis and monitor disease activity or treatment response.