Reference Interval:
| Test Number
| Components
| Reference Interval
| | 0050811 | Anti-Neutrophil Cytoplasmic Antibody, IgG
| < 1:20: Not significant
| | 0050526 | Myeloperoxidase Antibody
| Negative: 19 AU/mL or less
Equivocal: 20-25 AU/mL
Positive: 26 AU/mL or greater
| | 0050527 | Serine Protease 3 Antibody
| Negative: 19 AU/mL or less
Equivocal: 20-25 AU/mL
Positive: 26 AU/mL or greater
|
|
| Interpretive Data: |
Neutrophil Cytoplasmic Antibodies (C-ANCA = granular cytoplasmic staining, P-ANCA = perinuclear staining) are found in the serum of over 90% of patients with certain necrotizing systemic vasculitides, and usually in less than 5% of patients with collagen vascular disease or arthritis. Approximately 90% of patients with a P-ANCA pattern by IFA have antibodies specific for MPO. Approximately 85% of patients with a C-ANCA pattern by IFA have antibodies specific for PR3.
| ANCAs in Vasculitic Syndromes
| | Approximate % pos ANCA
| Approximate % of patients demonstrating
| | | Combined patterns
| C Pattern
| P Pattern
| | Wegener granulomatosis:
| | | | | -Active generalized
| 85-92
| 85-90
| 2-5
| | -Limited forms
| 60-67
| 85-90
| 2-5
| | -Inactive
| 30-35
| 85-90
| 2-5
| | Idiopathic Crescentic Glomerulonephritis
| 80
| some*
| majority*
| | Polyarteritis Nodosa
| 50
| 86
| 14
| | Churg-Strauss
| 50
| 80
| 20
| | Systemic lupus erythematosus (SLE)
| <10
| 0
| >90
| | Rheumatoid arthritis
| <5
| 0
| >90
| | Sjögren syndrome
| 25
| 0
| >90
| |
|
| Note: |
Specimens are screened by IFA on ethanol-fixed slides which allow differentiation of C and P patterns. If screen result is 1:20, titer and MPO/PR-3 Antibodies will be added.
Specimens are serially diluted and tested on ethanol fixed slides to establish titer and confirm pattern. All P-ANCA patterns are also tested on formalin-fixed slides to confirm P-ANCA by removing ANA receptor sites and maintaining cytoplasmic localization of myeloperoxidase.
|
| CPT Code(s): |
86255 ANCA; if reflexed, add 86256 ANCA titer and 83876 MPO; 83516 PR3
|