Anti-Saccharomyces Cerevisiae Antibodies, IgA and IgG
Label Mnemonic: ASCA
Epic Lab Code: LAB1260
Downtime Form: A-1a Immunopathology Requisition
5238 RCP
Collection Medium:
Red top tube 5 mL (Clot Activator)
Adult - 5 mL; red top tube Pediatric - 2 mL; red top tube
Testing Schedule:
Turn Around Time:
1 week
Reference Range:
Negative: <20 units Equivocal: 20-24 units Positive: >25 units
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 prevalent 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 repeatedly 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.
Enzyme-Linked Immunosorbent Assay Test (ELISA)
CPT Code:
83516 ASCIGG; 83516 ASCIGA