What role does tTG IgA play in Sport?

tTG IgA (tissue transglutaminase IgA antibodies) is a primary serological marker for celiac disease, an autoimmune condition triggered by gluten ingestion. In the context of sport, elevated tTG IgA may indicate undiagnosed celiac disease, which can impair athletic performance through malabsorption leading to iron deficiency anemia, chronic fatigue, gastrointestinal distress, and reduced recovery. Screening with tTG IgA is clinically indicated in athletes presenting with unexplained symptoms such as bloating, diarrhea, fatigue, or iron deficiency, especially in endurance sports where iron demands are high. However, the evidence for routine screening in asymptomatic athletes is limited; most data come from general medical populations. A positive result requires confirmatory small bowel biopsy. Caveats: false positives can occur (e.g., in IgA deficiency or other autoimmune conditions), and the test is not a direct measure of performance. The role of tTG IgA in sport is thus diagnostic rather than predictive. Evidence level: practice (clinical guidelines) with limited sport-specific studies. Testing should be guided by clinical suspicion, not universal screening.