What to watch with tTG IgA and Müdigkeit?

Elevated tTG-IgA with fatigue primarily suggests celiac disease. tTG-IgA is the first-line serological marker; a positive result should be confirmed by duodenal biopsy (human-strong). Fatigue may result from malabsorption (iron, vitamin B12, folate deficiency) or associated autoimmune conditions (e.g., Hashimoto thyroiditis). Non-celiac gluten sensitivity is also possible. Caveat: tTG-IgA can be falsely negative in IgA deficiency; then IgG-based tests (DGP-IgG) are indicated. Microbiome tests are not diagnostic here (see context).