Is tTG IgA useful for Müdigkeit?

tTG IgA (tissue transglutaminase IgA) is a well-established serological marker for celiac disease. Fatigue can be a symptom of undiagnosed celiac disease, especially when accompanied by other signs like diarrhea, bloating, iron deficiency, or weight loss. In such cases, the test is useful. However, fatigue is a highly nonspecific symptom; celiac disease prevalence is about 1 % in the general population. A positive tTG IgA result should be confirmed by duodenal biopsy. Importantly, in IgA deficiency (≈2 % of the population), the test can be falsely negative; then IgG-based tests (e.g., tTG IgG or DGP IgG) should be used. The test is not a general fatigue screening tool; it is only indicated when celiac disease is suspected. Without additional symptoms or risk factors, the likelihood of a positive result is low, and the test rarely explains fatigue. Evidence for its utility in isolated fatigue is weak. A thorough medical workup is recommended.