ANTI SACCHAROMYCES CERVISAE (ASCA) IGG ANTIBODY

The Anti-Saccharomyces cerevisiae (ASCA) IgG Antibody Test is a specialized blood test that detects Immunoglobulin G (IgG) antibodies against Saccharomyces cerevisiae, commonly known as baker's or brewer's yeast. This test is primarily used to support the diagnosis of Crohn's disease, a major type of Inflammatory Bowel Disease (IBD), and to help distinguish it from Ulcerative Colitis (UC).

Crohn's disease is a chronic autoimmune inflammatory disorder that can affect any part of the gastrointestinal tract, from the mouth to the anus. It causes persistent inflammation that may lead to abdominal pain, diarrhea, weight loss, fatigue, and nutritional deficiencies. In many individuals with Crohn's disease, the immune system produces ASCA IgG antibodies as part of an abnormal immune response to yeast antigens.

The ASCA IgG Antibody Test is commonly performed together with ASCA IgA, pANCA (Perinuclear Anti-Neutrophil Cytoplasmic Antibody), inflammatory markers, imaging studies, colonoscopy, and biopsy findings to improve diagnostic accuracy. While this test alone cannot confirm Crohn's disease, it provides valuable supportive evidence when interpreted alongside clinical findings.

Early diagnosis enables timely treatment, reducing disease progression and improving long-term outcomes.

Benefits of the Test

• Detects ASCA IgG antibodies with high specificity
• Supports diagnosis of Crohn's disease
• Helps differentiate Crohn's disease from ulcerative colitis
• Assists in evaluating inflammatory bowel disease (IBD)
• Supports treatment planning and disease assessment
• Requires only a peripheral blood sample
• Complements other gastrointestinal autoimmune investigations

Why Doctors Recommend This Test

Doctors may recommend this test if a patient has:

• Chronic diarrhea
• Persistent abdominal pain
• Blood in the stool
• Unexplained weight loss
• Recurrent abdominal cramps
• Chronic intestinal inflammation
• Suspected Crohn's disease
• Family history of inflammatory bowel disease
• Abnormal colonoscopy findings
• Persistent gastrointestinal symptoms

Preparation Before Test

Sample Required

• Peripheral venous blood sample (Serum)

Preparation Guidelines

• No fasting is generally required.
• Continue medications unless advised otherwise by your physician.
• Inform your healthcare provider about any gastrointestinal or autoimmune disorders.
• Follow laboratory instructions before sample collection.

Reporting Time

Results are generally available within 3–7 working days, depending on laboratory methodology.

Who Should Take This Test?

This test is recommended for:

• Individuals with suspected Crohn's disease
• Patients with inflammatory bowel disease symptoms
• Individuals with chronic diarrhea and abdominal pain
• Patients with unexplained intestinal inflammation
• Individuals requiring differentiation between Crohn's disease and ulcerative colitis
• Patients referred by gastroenterologists or immunologists

Clinical Significance

Elevated ASCA IgG antibodies may indicate:

• Crohn's Disease
• Inflammatory Bowel Disease (IBD)
• Chronic Intestinal Inflammation
• Autoimmune Gastrointestinal Disorders

Common symptoms associated with Crohn's disease include:

• Chronic diarrhea
• Abdominal pain and cramping
• Blood in the stool
• Weight loss
• Fatigue
• Loss of appetite
• Fever
• Nutritional deficiencies
• Mouth ulcers
• Perianal disease (in some patients)

A positive ASCA IgG antibody result supports the diagnosis of Crohn's disease but should always be interpreted together with clinical history, physical examination, colonoscopy, biopsy findings, imaging studies, pANCA testing, inflammatory markers, and other laboratory investigations.