Antineutrophil Cytoplasmic Antibodies (ANCA)

Casandra

Casandra Test Code LC79081Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 162388CPT Code 86037

Antineutrophil Cytoplasmic Antibodies (ANCA)

Clinical Use

Use

Antineutrophil cytoplasmic autoantibodies (ANCA) are a serological marker associated with vasculitis and glomerulonephritis. Specifically, ANCA have been found (at frequencies ranging from 70% to 90%) in patients with active Wegener granulomatosis, microscopic polyarteritis nodosa, and idiopathic crescentic glomerulonephritis (with manifestations ranging from kidney-limited disease to extrarenal systemic disease, including pulmonary-renal syndromes). Glomerular lesions in patients with ANCA-associated systemic vasculitis or renal-limited disease are virtually identical. Normal controls are negative for ANCA and <10% of patients with other renal diseases are positive. ANCA may be directly involved in the pathogenesis of the vascular injury that causes the clinical manifestations in ANCA-associated disease.

Special Instructions

Antineutrophil cytoplasmic autoantibodies exhibiting pANCA or cANCA patterns are detected using indirect immunofluorescent antibody (IFA) techniques. Positive patient sera with perinuclear or nuclear patterns are repeated using a formalin-fixed substrate to differentiate true pANCA antibodies from interference with antinuclear antibodies.

Limitations

The presence of positive fluorescence exhibiting P-ANCA or C-ANCA patterns alone is not specific for the diagnosis of Wegener's Granulomatosis or microscopic polyangiitis. Decisions about treatment should not be based solely on ANCA IFA results. It is recommended to follow up positive sera with both PR-3 and MPO-ANCA enzyme immunoassays, as some serum samples are positive only by EIA.

Test Details