ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES VASCULITIS PANEL

General Information

HLAB/HOL Code: VASCU
UPHSM LIS Test #: 026566
Schedule:
Testing Time:
Testing Lab: UP Health System-Marquette

Specimen Info
Only 1 specimen type required, unless otherwise specified

Volume: 1.0mL
Temperature: Refrigerated
Tube Type: Serum
Collection Info:
Clients will be called to order reflex test ANCY – Antineutrophil Cytoplasmic Antibodies if desired when screening results are equivocal or positive.  Please be sure to include sufficient sample to allow for reflex testing if this is desired (an extra 1.0mL of serum). Please see ANCY in test catalog for more details.

Specimen Acceptability

Avoid hemolysis

Methods

Multiplex Flow Immunoassay

Reference Range

MPO REFERENCE VALUES
<0.4 U (negative)
0.4-0.9 U (equivocal)
> or =1.0 U (positive)
Reference values apply to all ages.

INTERPRETATION  
A positive result has a high predictive value for microscopic polyangiitis (MPA) in patients with negative test results for systemic lupus erythematosus (antinuclear antibodies) and Goodpasture syndrome (glomerular basement membrane antibody). A negative result significantly diminishes the likelihood that a patient has MPA.
While myeloperoxidase levels often decline following successful treatment of MPA, specific guidelines for this clinical purpose are not available.
While sequential measurements of MPO may be used to follow treatment response or to monitor disease activity in patients with MPA, results should not be exclusively relied upon to assess response to treatment or disease activity.

GBM REFERENCE VALUES
<1.0 U (negative)                    
> or =1.0 U (positive)
Reference values apply to all ages.

INTERPRETATION  
Positive results are consistent with Goodpasture syndrome. Glomerular basement membrane antibodies detected by immunoassay have been reported to be highly specific for Goodpasture syndrome. The sensitivity of this test approaches 87% in untreated patients with systemic disease.
CAUTIONS  
A positive test for glomerular basement membrane (GBM) antibodies cannot be relied upon exclusively to establish the diagnosis of a disease mediated by GBM antibodies. Weakly-positive test results may occur in other immune-mediated diseases, and renal or lung biopsy is often required to establish the diagnosis.

PR3 REFERENCE VALUES  
<0.4 U (negative)
0.4-0.9 U (equivocal)
> or =1.0 U (positive)
Reference values apply to all ages.

INTERPRETATION  
Proteinase 3 antineutrophil cytoplasmic antibodies (PR3 ANCA) are detectable in nearly all patients with severe active Wegener granulomatosis (WG).(2) The presence of PR3 ANCA is a specific diagnostic indicator of WG; less than 2% of positive results occur in patients who do not have the disease.
A negative result for PR3 ANCA diminishes the likelihood that a patient has active WG; but, approximately 20% of patients with limited WG may test negative for PR3 ANCA.(3)
The levels of PR3 ANCA often decline following successful treatment of patients with WG. Nevertheless, follow-up testing for PR3 ANCA to evaluate clinical status in treated patients should be used with caution as the levels of antibodies may correlate poorly with clinical status in some patients.