Antiproteinase 3 (PR3) Antibodies

Test ID:

704722

CPT code:

83520

Synonyms:

cANCA-specific Antibody

Clinical Use:

For diagnosis and monitoring inflammatory activity in primary systemic small vessel vasculitides. Antineutrophil antibodies are best demonstrated in these diseases by using a combination of IFA and EIAs that detect ANCA specific for PR3-ANCA or MPO-ANCA. Presence of anti-MPO antibodies are highly specific for idiopathic and vasculitis associated crescentic glomerulonephritis, classic polyarteritis nodosa, Churg-Strauss syndrome, and polyangiitis overlap syndrome without renal involvement.

Presence of anti-PR3 antibodies are highly specific for Wegener granulomatous (WG) disease, for which the sensitivity is reported to be 98%. Some patients with WG have pANCA with MPO specificity. About 60% of patients with microscopic polyangiitis or pauci-immune segmental necrotizing glomerulonephritis have pANCA with MPO specificity but 30% have cANCA with PR3 specificity. Levels of anti-PR3 or anti-MPO are elevated during active phases of disease and lower during remission and can be monitored for management of disease.