Lab Information Manual

Laboratory:

Clinical Immunology

Test Name:

PROTEINASE 3 ANTIBODY (PR3) - (S)

Test Code: PR3

Clinical Information:

Alternate Name(s):
Autoantibodies to Proteinase 3

PR3 (Proteinase 3 Ab), S

PR3 (Proteinase 3) Antineutrophil Cytoplasmic Antibodies

PR3 ANCA

Test Indications: Presence of PR3 IgG antibodies may aid in evaluating patients with clinical features of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, specifically granulomatosis with polyangiitis (GPA), microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. May be useful to monitor disease and/or treatment response.

PR3 can be ordered as a standalone test to monitor antibody levels in patients with established vasculitis. PR3 is also automatically reflexed for samples positive for cANCA and those with Indeterminate ANCA results.

Collection Devices:

Preferred Device:

1 - Serum Separator (SST) Tube(s) - Full Tube Collection

Serum Separator (SST) Tube(s) - Full Tube Collection
Manufacturer: Becton Dickinson

Catalogue #: 367986

Specimen Required:

Serum: 1.0 mL

Refrigerated: 7 days

Frozen: 30 days

Referral:

Serum: 1.0 mL

Shipping & Storage: Separate serum and ship refrigerated, or frozen if greater than 7 days from time of collection.

Testing Laboratory (MB): St. Boniface Hospital Immunology Laboratory

Requisition:

_SH Immunology Autoimmune Laboratory Requisition (R250-10-85)

Reference Values:

Reference Intervals: 0.0 – 24.9 AU/ml
A negative result does not necessarily exclude autoimmune disease. Positive results should not be interpreted in isolation and must be correlated with relevant clinical findings.

Method of Analysis: The IDS PR3 IgG assay is based on chemiluminescence technology. Patient serum is incubated with magnetic particles coated with the specific antigen. Following the washing step after the first incubation, an anti-human IgG antibody labelled with acridinium is added, followed by a subsequent incubation step. The magnetic particles are captured using a magnet and a wash step performed to remove any unbound analyte. Trigger reagents are added; the resulting light emitted by the acridinium label is directly proportional to the concentration of anti-PR3 IgG in the sample.

Reference: IDS PR3 Instructions for Use, IS-AI1702II V07, 18-11-2025

Availability:

Weekdays

TAT: 3-5 Days