Anti-Saccharomyces Cerevisiae Antibodies, IgA and IgG
Order Code: ASCA
Order Form: Immunopathology Requisition
Specimen:
Serum
Collection Medium:
Red top tube
Minimum:
Adult - 5 mL; red top tube Pediatric - 2 mL; red top tube
Testing Schedule:
Weekly
Analytic Time:
1 week
Reference Range:
Negative: <20 units Equivocal: 20-24 units Positive: >25 units
Comments:
The results will be obtained with the INOVA QUANTA Lite™ ELISA. Assay values obtained with different manufacturers' methods may not be used interchangeably. The magnitude of the reported antibody levels can not be correlated to an endpoint titer. ASCA testing may be clinically useful in the evaluation of suspected inflammatory bowel disease, including Crohn's disease and ulcerative colitis (UC). ASCA is significantly more prevelant in Crohn's disease than in UC or in healthy individuals. Published studies of Crohn's disease have reported IgG ASCA test sensitivity for CD is about 74% while IgA ASCA is about 49% sensitive. About 25% of CD patients are repeatably negative for ASCA, therefore a negative result does not rule out CD. The best specificity for CD is obtained when both IgG and IgA ASCA's are positive. There are published reports of 95-100% specificity with dual IgG and IgA positivity. Our own disease control testing (patients with a variety of GI and liver diseases) revealed 85% specificity with false positives in 1 patient with Mycobacterial granulomatous hepatitis, 1 patient with alcoholic hepatitis and 1 patient with acute colitis, probably UC.
Methodology:
Enzyme-Linked Immunosorbent Assay Test (ELISA)
Sample Processing:
Centrifuge at 3500 RPM for 5 minutes.
Aliquot serum into labeled container and cap.
Relevant clinical information must be submitted with specimen in order to provide correct interpretation of test results.
Sample Storage:
Refrigerate serum 2-8°C.
Transport Instructions:
Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Ship at ambient temperature.
CPT Code:
83520 ASCIGG; 83520 ASCIGA