Proteinase 3 Antibodies, IgG
Label Mnemonic: PR3
Epic Lab Code: LAB1344
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:
Proteinase 3 (PR3) antibodies are used for evaluating patients suspected of having Wegener granulomatosis (WG). Tests for PR3 antibodies should be employed with clinical history, physical examination, and other serologic tests in the initial diagnostic evaluation of patients with clinical features of vasculitis. It is recommended that initial workup of such patients include "Neutrophil Cytoplas.Screen (ANCA)" (LAB1327). Proteinase 3 antibodies and myeloperoxidase antibodies are performed if ANCA screen is positive or inconclusive.

Titers to PR3 antibodies may be useful to follow treatment response.
Comments:
Assay methodology and reference ranges changed February 5, 2013.

References:
Finkielman JD et al. ANCA are detectable in nearly all patients with active severe Wegener's granulomatosis. Am J Med 2007; 643:e9- e14.

Russel KA et al. Detection of anti-neutrophil cytoplasmic antibodies under actual clinical testing conditions. Clin Immunol 2002; 103:196- 203.

Savige J et al. International consensus statement on testing and reporting of antineutrophil cytoplasmic antibodies (ANCA). Am J Clin Pathol 1999; 111:507-513.
Methodology:
Multiplex flow immunoassay
CPT Code:
83520