Myeloperoxidase (MPO) Antibody and Serine Proteinase 3 (PR3) Antibody with Reflex to Anti-Neutrophil Cytoplasmic Antibody, IgG by IFA
Also known as: ANCA-PN
Use
This panel is commonly used as a first-line reflex test for the evaluation of ANCA-associated vasculitis. Testing for MPO and PR3 antibodies helps identify specific autoantibodies that are markers of ANCA-associated diseases, such as microscopic polyangiitis and granulomatosis with polyangiitis. The reflex to ANCA IFA is performed to further distinguish C-ANCA from P-ANCA patterns, which are significant in diagnosing specific vasculitic processes.
Special Instructions
If MPO and/or PR3 results are equivocal or positive, then ANCA by IFA will be added. Additional charges apply. Specimens are screened by IFA on ethanol-fixed neutrophils, formalin-fixed neutrophils, and HEp-2 slides that allow differentiation of C- and P-ANCA patterns.
Limitations
The presence of ANCA by IFA without accompanying MPO or PR3 antibodies may require further clinical correlation and investigation to determine the significance. False negatives can occur if antibody levels are below the detection limit of the assays, and false positives can be associated with a variety of non-vasculitic conditions. Interpretation of results should always be done in conjunction with the patient's clinical presentation and other laboratory findings.
New York Approved
Methodology
Immunoassay (Semi-Quantitative Multiplex Bead Assay)
Biomarkers
LOINC Codes
- 6969-0
- 6968-2
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Separate serum from cells ASAP or within 2 hours of collection.
Storage Instructions
Refrigerated.
Causes for Rejection
CSF, plasma, urine, or other body fluids. Contaminated, hemolyzed, or severely lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 2 weeks |
| Frozen | 1 year (avoid repeated freeze/thaw cycles) |
Other tests from different labs that may be relevant