Proteinase 3 Antibodies, IgG, Serum

Casandra

Casandra Test Code MC72786Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID PR3CPT Code 83516

Proteinase 3 Antibodies, IgG, Serum

Clinical Use

Use

Proteinase 3 antibodies, also known as PR3-ANCA, are associated with certain types of ANCA-associated vasculitis including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). This test is useful in evaluating patients for these conditions, distinguishing between GPA and other forms of ANCA-associated vasculitis when used in conjunction with myeloperoxidase antibody and cytoplasmic neutrophil antibody testing, and monitoring treatment response in patients with proteinase 3 antibodies.

Special Instructions

To distinguish between granulomatosis with polyangiitis and other forms of ANCA-associated vasculitis, it is recommended to also order MPO / Myeloperoxidase Antibodies, IgG, Serum or ANCA / Cytoplasmic Neutrophil Antibodies, Serum. Alternatively, the VASC / Antineutrophil Cytoplasmic Antibodies Vasculitis Panel, Serum may be ordered, which initially tests for MPO and proteinase 3 antibodies with reflex to ANCA when appropriate.

Limitations

A positive result for proteinase 3 (PR3)-anti-neutrophil cytoplasmic antibodies (ANCA), myeloperoxidase (MPO)-ANCA, or ANCA by indirect immunofluorescence is not solely diagnostic for any ANCA-associated vasculitis and must be interpreted in the clinical context of the patient. Negative results for PR3-ANCA, MPO ANCA, and ANCA by IIF do not exclude the possibility of ANCA-associated vasculitis. Monitoring reactivity of PR3-ANCA or MPO-ANCA should not be relied upon solely to evaluate treatment response or assess the risk of disease flare.

Test Details

FDA Approved