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Serum or Plasma Immunoassay for Anti-Saccharomyces Cerevisiae Antibodies (ASCA)

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

This test measures antibodies in your blood that may indicate an immune response to *Saccharomyces cerevisiae* (a type of yeast). It’s often used to help diagnose conditions like inflammatory bowel disease (IBD), such as Crohn’s disease.

Quick summary

["This test helps identify possible autoimmune responses linked to gut inflammation."]

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

Key facts at a glance

LOINC
6558-1
Short code
S pyo Ag Spec Ql IA
Synonyms
S pyo Ag Spec Ql IA
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 This Test Measures

The ASCA test detects specific antibodies produced by your immune system in response to yeast proteins. These antibodies can be elevated in people with certain gastrointestinal conditions, particularly those with chronic inflammation of the intestines.

Why It Might Be Ordered

Your doctor may recommend this test if you have symptoms like persistent diarrhea, abdominal pain, weight loss, or a history of IBD. It’s sometimes used alongside other tests to narrow down possible causes of digestive issues.

How the Test Works

A blood sample is taken, and the serum or plasma is analyzed using an immunoassay method to detect the presence of ASCA antibodies. The result helps determine if your immune system is reacting to yeast proteins in a way that may relate to gut inflammation.

What the Results Could Mean

Positive results suggest a higher likelihood of certain autoimmune or inflammatory conditions, but they’re not definitive. Doctors will consider your symptoms, medical history, and other test results to make a diagnosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: ASCA Antibodies and Inflammatory Bowel Disease

Short name

ASCA Antibody Test

Frequently asked questions

What symptoms might lead to this test?
Symptoms such as persistent abdominal pain, unexplained weight loss, chronic diarrhea, or a history of digestive issues like IBD may prompt your doctor to order an ASCA test. It’s also sometimes used in research or to monitor certain conditions.
How accurate is this test?
ASCA tests are not 100% accurate. They’re often used as a screening tool alongside other tests, like endoscopies or stool samples, to support a diagnosis. False positives or negatives can occur, so results should be interpreted by a healthcare provider.
Can this test be done at home?
No, this test requires a blood sample collected by a healthcare professional. Results are typically reviewed by a lab and shared with your doctor.
  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