ANCA (Anti-Neutrophil Cytoplasmic Antibodies) are autoantibodies directed against proteins in neutrophil cytoplasm.

The ANCA Profile identifies specific antibody patterns:

c-ANCA (cytoplasmic pattern): Usually targets Proteinase 3 (PR3).

p-ANCA (perinuclear pattern): Usually targets Myeloperoxidase (MPO).

Clinical uses include:

Diagnosing systemic vasculitis (GPA, MPA, EGPA).

Differentiating autoimmune vasculitis from other inflammatory conditions.

Monitoring disease activity and treatment response.

The test is performed using a blood sample, typically via immunofluorescence and ELISA.

Analyte: Autoantibodies against neutrophil cytoplasmic antigens.

Patterns Detected:

c-ANCA (PR3 antibodies) → granulomatosis with polyangiitis.

p-ANCA (MPO antibodies) → microscopic polyangiitis, EGPA.

Normal Result: Negative (no ANCA detected).

Positive Result: Presence of ANCA → indicates autoimmune vasculitis.

Clinical Use:

Confirms diagnosis of ANCA-associated vasculitis.

Helps differentiate between subtypes of vasculitis.

Guides treatment and monitoring.