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Anti-Saccharomyces cerevisiae Antibodies IgA (ASCA IgA)

Published: July 27, 2026Updated: August 25, 2026

ASCA IgA measures the level of IgA antibodies against Saccharomyces cerevisiae, a type of yeast, in the blood. Elevated levels are often associated with inflammatory bowel diseases such as Crohn's disease and ulcerative colitis.

Quick summary

ASCA IgA is a biomarker used to help diagnose inflammatory bowel diseases.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
U/mL
Clinical utility
diagnostic
Result kind
qualitative
FDA-cleared
Roche ASCA IgA, Vircell ASCA, Euroimmun ASCA IgA
interpretation: {"text":"0–20 U/mL: The level of ASCA IgA antibodies is within the normal range.","label":"Normal"}; {"text":">20 U/mL: The level of ASCA IgA antibodies is elevated, which may indicate an inflammatory bowel disease.","label":"Elevated"}

ASCA IgA is an immunological biomarker that detects the presence of IgA antibodies against Saccharomyces cerevisiae, a yeast commonly found in foods and beverages. The presence of these antibodies can indicate an immune response triggered by these antigens.

Elevated levels of ASCA IgA are frequently observed in patients with Crohn's disease and, to a lesser extent, in those with ulcerative colitis. This makes ASCA IgA a useful tool in differentiating between these inflammatory bowel diseases.

While ASCA IgA is not diagnostic on its own, it is often used in conjunction with other clinical findings and tests to support a diagnosis of inflammatory bowel disease. A result above the reference range (0–20 U/mL) may warrant further investigation.

Frequently asked questions

What does a high ASCA IgA level mean?
A high ASCA IgA level may indicate the presence of an inflammatory bowel disease, such as Crohn's disease or ulcerative colitis.
Can ASCA IgA levels change over time?
Yes, ASCA IgA levels can fluctuate with disease activity and treatment. Regular monitoring may be necessary.
  1. 1
    Mayo Clinic: Inflammatory Bowel DiseaseSource
  2. 2
    Lab Tests Online: ASCASource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

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Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy