Transglutaminase IgG (tTG-IgG) is a blood test that detects IgG antibodies against tissue transglutaminase, an enzyme in the intestinal lining. It is mainly used to help diagnose celiac disease, especially in individuals with IgA deficiency or unclear tTG-IgA results, by indicating an immune reaction to gluten.
Symptoms that might indicate a need for testing include gastrointestinal issues like chronic diarrhea and abdominal pain, as well as extraintestinal symptoms such as anemia, dermatitis herpetiformis (a skin rash), and growth problems in children, all of which could suggest celiac disease.
The test requires a blood sample from the patient. This sample is analyzed in a laboratory to measure the levels of IgG antibodies against tissue transglutaminase. Elevated levels of these antibodies suggest an immune reaction to gluten.
A positive result typically indicates an autoimmune response to gluten, as seen in celiac disease, where the body’s immune system mistakenly targets the small intestine. This reaction is triggered by the ingestion of gluten-containing foods.
The tTG-IgG test is recommended for individuals who show symptoms of celiac disease but have an IgA deficiency, making the tTG-IgA test less useful. Symptoms prompting this test include chronic diarrhea, abdominal pain, bloating, weight loss, and malnutrition.