Is tTG IgA useful for fatigue?

The tTG IgA test (tissue transglutaminase antibodies) is a well-established serological marker for celiac disease. Fatigue can be a presenting symptom of untreated celiac disease, especially in adults with atypical or subclinical presentations. However, the test is not useful as a general screening tool for fatigue because the prevalence of celiac disease in the general population is only about 1 %. A positive tTG IgA result should be confirmed by duodenal biopsy before recommending a gluten-free diet. If negative but clinical suspicion remains, additional markers such as IgA endomysial antibodies or HLA-DQ2/DQ8 typing may be considered. The evidence for using tTG IgA in isolated fatigue is weak; it is only recommended when there is clinical suspicion (e.g., gastrointestinal symptoms, iron deficiency, or family history). Without these risk factors, the predictive value is low, and false positives can cause unnecessary anxiety and dietary restrictions. In summary, tTG IgA is useful when celiac disease is a differential diagnosis for fatigue, but not as a general fatigue screening test.