Anti-endomysial antibody detection is of no benefit as an adjunct to IgA anti-tissue transglutaminase antibodies in the serological diagnosis of coeliac disease

Objective The anti-endomysial antibody (EMA) immunofluorescence test is recommended by some clinical guidelines as an adjunct to immunoglobulin A anti-tissue transglutaminase (TTG) antibody in coeliac disease (CD) diagnosis. However, dual testing can complicate interpretation. We assessed the diagnostic value of EMA alongside TTG. Method We retrospectively analysed patients tested for TTG and EMA between 2018 and 2019 at a single laboratory. 587 patients were categorised into two groups: TTG 7–10 U/mL (‘borderline’) and TTG >10 U/mL. CD was confirmed by duodenal biopsy; if unavailable, TTG ≥100 U/mL (10×upper limit of normal) was diagnostic, serologically. Results Biopsies were performed in all borderline cases (n=41). Among 23 EMA-negative patients, 17 (74%) had biopsy-confirmed CD. 12 of 18 (67%) EMA-positive patients had CD. EMA showed poor sensitivity (0.4138) and specificity (0.5000). Fisher’s exact test found no association between EMA and biopsy results (p=0.7341), indicating EMA’s limited diagnostic value in borderline cases. In the TTG >10 U/mL group (n=546), 523 were EMA-positive (511 with CD, 98%). Of 23 EMA-negative patients, 14 (61%) had CD. Despite a statistically significant association with CD (p