Myeloperoxidase Antibodies, IgG
Label Mnemonic: MPO
Epic Lab Code: LAB1326
Downtime Form: A-1a General Laboratory Requisition
Chemistry
6240 RCP
356-3527
Specimen(s):
Serum
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
Adult - 5 mL; red top tube
Pediatric - 2 mL; red top tube
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
3 hours (upon receipt in laboratory)
Reference Range:
Negative: < 0.4 antibody index AI
Equivocal: 0.4-0.9 AI
Positive: 1.0 AI or greater
Interpretive Data:
Myeloperoxidase (MPO) antibodies are used for evaluating patients suspected of having immune-mediated vasculitis, especially microscopic polyangiitis (MPA), when used in conjunction with clinical history, physical examination, and other autoantibody tests.

Autoantibodies to MPO occur in several diseases and may be involved in the pathogenesis of MPA. MPO autoantibodies are not specific for MPA and may also be detected in patients with Goodpasture syndrome, systemic necrotizing glomerulonephritis, and Churg-Strauss syndrome.

Titers to MPO antibodies may be useful to follow treatment response.
Comments:
Assay methodology and reference ranges changed February 5, 2013.

References:
Russel KA et al. Detection of anti-neutrophil cytoplasmic antibodies under actual clinical testing conditions. Clin Immunol 2002; 103:196- 203.
Methodology:
Multiplex flow immunoassay
CPT Code:
83520