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Serum Immunoassay for Anti-Saccharomyces Cerevisiae Antibodies (ASCA)

Published: August 9, 2026Updated: August 16, 2026

This test measures antibodies against *Saccharomyces cerevisiae* (a type of yeast), which may help identify an autoimmune condition affecting the intestines or kidneys.

Quick summary

["ASCA antibodies may signal inflammatory bowel disease or other autoimmune gut/kidney disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
47348-8
Short code
S pneum Da 19A IgG 2:1 Ser-Rto
Synonyms
S pneum Da 19A IgG 2:1 Ser-Rto
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is ASCA Used For?

ASCA testing is often used to support a diagnosis of **Crohn’s disease** or **primary sclerosing cholangitis**, two conditions where the immune system attacks the digestive tract. It may also help assess autoimmune kidney diseases or other inflammatory conditions.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The serum portion is then tested for specific antibodies against yeast proteins using an immunoassay method.

What Does a Positive Result Mean?

A positive result suggests a higher likelihood of autoimmune inflammation in the gut or kidneys, but it is not definitive on its own. Your doctor will consider clinical symptoms, other test results, and medical history.

What Are Common Causes of ASCA Positivity?

Positive ASCA results are most strongly linked to **Crohn’s disease** and **primary sclerosing cholangitis**, though they can appear in other autoimmune or inflammatory conditions. False positives may occur in rare cases.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ASCA Antibody Test

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend ASCA testing if you have symptoms like persistent diarrhea, abdominal pain, or unexplained inflammation in the digestive tract, especially if other tests (like endoscopy or stool studies) are inconclusive.
What do I need to do before the test?
No special preparation is needed, but inform your doctor about any medications (especially steroids or immunosuppressants) or recent infections that could affect results.
Can ASCA results change over time?
Yes, ASCA levels may fluctuate with disease activity. Regular monitoring can help track progression or response to treatment, but results should always be interpreted alongside your overall health picture.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy