Transglutaminase IgG (tTG-IgG) er en spesifikk antistofftest som brukes ved diagnostisering av cøliaki og andre glutenrelaterte lidelser. Denne testen måler IgG-antistoffene mot vevstransglutaminase, et enzym som finnes i tarmens slimhinne. I motsetning til den vanligere Transglutaminase IgA (tTG-IgA) testen, brukes tTG-IgG vanligvis når en pasient har en IgA-mangel eller når IgA-testresultatene er tvetydige. Den bidrar til å identifisere glutenintoleranse ved å indikere en immunrespons som oppstår når en person med cøliaki inntar gluten, noe som fører til en autoimmun reaksjon som skader tynntarmen.
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.