Specimen Collection Manual and Test Catalog

0.5 mL serum; minimum 0.5 mL

Allow to clot. Centrifuge and submit 0.5 mL serum.

Refrigerated (preferred). Room temperature (stable 8 hours) and frozen specimens also acceptable.

Room temperature: 8 hours. 2-8°C: 48 hours. Frozen: 6 months.

Specimen stability exceeded; specimen grossly hemolyzed.

MPO Antibody Negative <3.5 U/mL
PR3 Antibody Negative <2.0 U/mL

Anti-MPO: Negative <3.5 U/mL 
Equivocal 3.5- 5.0 U/mL 
Positive >5.0 U/mL

Anti-PR3: Negative <2.0 U/mL 
Equivocal 2.0-3.0 U/mL
Positive >3.0 U/mL

If either MPO or PR3 result is “equivocal”, test progresses to ANCA-IFA at an additional charge.

anti-MPO, anti-PR3 antibody detection

myeloperoxidase, proteinase 3, ANCA, MPO, anti-MPO, PR3, anti-PR3, ANCA Battery, ANCAB

The presence of anti-neutrophil associated antibodies (ANCA) can be used in conjunction with other tests and clinical findings to aid in the assessment of systemic vasculitis. This panel tests for the two most common anti-neutrophil antibodies, anti-myeloperoxidase (MPO) and anti-proteinase 3 (PR3). Anti-PR3 is more commonly associated with Granulomatosis with Polyangiitis (GPA, formerly known as Wegener's Granulomatosis), while anti-MPO is commonly associated with Microscopic Polyangiitis (MPA), although there is considerable overlap in positivity between conditions. Antineutrophil antibodies can also be observed in related ANCA-associated vasculitides (AAV) such as pauciimmune-necrotizing crescentic glomerulonephritis and Churg–Strauss syndrome, and is also seen in some patients with other autoimmune conditions such as IBD, PSC, and RA. For follow-up and trending of known cases, the appropriate stand-alone antibody test (anti-MPO LAB2730 or anti-PR3 LAB2942) should be used. If anti-MPO/PR3 are negative but strong clinical suspicion of autoimmune vasculitis remains, or for follow-up of known MPO/PR3-negative, ANCA-positive vasculitis, stand-alone ANCA-IFA can be ordered (LAB5192)