False-negative IgA Anti-tissue Transglutaminase

The expanding knowledge about gluten-related autoimmunity led to a serology-based step-wised approach to diagnose celiac disease that might be misleading due to laboratory techniques. We present a rare case associating initial false-negative anti-transglutaminase IgA antibodies while CD was confirmed by IgG anti-transglutaminase and subsequent duodenal biopsy.