Sign in →

Test ID AASCA Saccharomyces cerevisiae Antibody, IgA, Serum

Reporting Name

Saccharomyces cerevisiae Ab, IgA, S

Useful For

Helping clinicians distinguish between ulcerative colitis and Crohn’s disease in patients suspected of having inflammatory bowel disease

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reference Values

Negative: ≤20.0 U

Equivocal: 20.1-24.9 U

Weakly positive: 25.0-34.9 U

Positive: ≥35.0 U

Reference values apply to all ages.

Day(s) and Time(s) Performed

Monday through Friday; 5 p.m.

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
AASCA Saccharomyces cerevisiae Ab, IgA, S 47320-7


Result ID Test Result Name Result LOINC Value
AASCA Saccharomyces cerevisiae Ab, IgA, S 47320-7

Clinical Information

Inflammatory bowel disease (IBD) refers to 2 diseases, ulcerative colitis (UC) and Crohn's disease (CD), that produce inflammation of the large or small intestines.(1) The diagnoses of both diseases are based on clinical features, the results of barium X-rays, colonoscopy, mucosal biopsy histology, and in some cases operative findings and resected bowel pathology and histology.


Recently, patients with IBD have been shown to have antibodies in serum that help distinguish between CD and UC.(2) Patients with UC often have measurable neutrophil-specific antibodies, which react with as yet uncharacterized target antigens in human neutrophils; whereas, patients with CD often have measurable antibodies of the IgA and/or IgG isotypes, which react with cell wall mannan of Saccharomyces cerevisiae strain Su 1.


In IBDP / Inflammatory Bowel Disease Serology Panel, Serum, anti-Saccharomyces cerevisiae antibodies (ASCA) and neutrophil-specific antibodies (NSA) are measured. The finding of NSA with normal levels of IgA and IgG ASCA is consistent with the diagnosis of ulcerative colitis (UC); the finding of negative NSA with elevated IgA and IgG ASCA is consistent with Crohn's disease (CD).


NSA are detectable in approximately 50% of patients with UC.


Elevated levels of either IgA or IgG ASCA occur in approximately 55% of patients with CD.


Approximately 40% of patients with CD have elevated levels of both IgA and IgG ASCA.


Employed together, the tests for NSA and ASCA have the following positive predictive values (PPV) for UC and CD, respectively:(2)

-NSA-positive with normal levels of IgA and IgG ASCA, PPV of 91%

-NSA-negative with elevated levels of IgA and IgG ASCA, PPV of 90%

Clinical Reference

1. The Autoimmune Diseases: Inflammatory Bowel Diseases. Edited by NR Rose, IR Mackay. New York, NY, Elsevier Academic Press, 2008

2. Sandborn WJ, Loftus EV Jr, Homburger HA, et al: Evaluation of serological disease markers in a population-based cohort of patients with ulcerative colitis and Crohn's disease. Inflamm Bowel Dis 2001 Aug;7(3):192-201

Analytic Time

Same day/1 day

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request Form (T728) with the specimen (