Is there utility in testing IgA-endomysial antibodies in patients with weak-positive or equivocal IgA-tissue transglutaminase antibodies in the diagnosis of coeliac disease? A critique of current NICE guidance (NG20).

This article evaluates the clinical utility of IgA-endomysial antibody (IgA-EMA) testing following weak-positive or positive IgA-tissue transglutaminase antibody (IgA-tTGA) results in diagnosing coeliac disease (CD). The study found that a negative IgA-EMA does not reliably exclude CD, with negative predictive values of 41% for weak-positive and 0% for positive IgA-tTGA results, based on duodenal biopsy confirmation. Additionally, patients with negative IgA-EMA were significantly less likely to undergo duodenal biopsy, suggesting clinicians may inappropriately use negative IgA-EMA results to rule out CD. The authors recommend restricting IgA-EMA testing to confirmatory use in a non-biopsy diagnostic pathway for patients with very high IgA-tTGA levels and advise against using negative IgA-EMA to exclude CD in cases of weak-positive or positive IgA-tTGA, calling for updates to current UK NICE guidelines.