Is tTG IgA useful for gut health?

The tTG IgA test (tissue transglutaminase IgA) is a well-established serological marker for celiac disease, an autoimmune condition triggered by gluten that damages the small intestine. It is useful for gut health specifically in the context of suspected celiac disease – symptoms like chronic bloating, diarrhea, fatigue, or nutrient malabsorption. However, it is not a general gut health test. It does not detect other common gut issues such as irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), or inflammatory bowel disease (IBD). False positives can occur (e.g., in IgA deficiency), and false negatives if the patient is already on a gluten-free diet. Evidence for celiac diagnosis is strong (human-strong), but for broader gut health assessment the test is not appropriate. A comprehensive gut health evaluation may require stool tests, breath tests, or endoscopy. Consumers should understand that a positive tTG IgA requires confirmation via biopsy. Without specific celiac suspicion, this test is not recommended as a general wellness tool.