title: Reliance on serum endomysial antibody testing underestimates the true prevalence of coeliac disease by one fifth.
abstract: BACKGROUND
  Although IgA endomysial antibody (EmA) is currently the serologic test of choice in selecting suspected coeliac patients for duodenal biopsies, false-negative cases have been reported and may be more common than previous studies suggest. We assessed the sensitivity of EmA for patients with biopsy-confirmed villous atrophy (VA).
  
  
  METHODS
  We studied 89 patients without IgA deficiency for whom biopsy had not been primarily prompted by a positive EmA result. VA was graded as partial, subtotal, or total (PVA, STVA, TVA). Serum EmA was assayed with indirect immunofluorescence.
  
  
  RESULTS
  The sensitivity of EmA for VA was 78% (69 of 89) and was similar for PVA (79%) and ST/TVA (77%). Only 4 of the 20 EmA-negative patients had increased serum IgA-class antigliadin antibody levels as measured with enzyme-linked immunosorbent assay. All seronegative patients who complied with dietary gluten exclusion responded clinically, with histologic improvement after 12 months in 8 (67%) of 12 patients who had follow-up biopsies.
  
  
  CONCLUSIONS
  EmA-negative coeliac disease is common. Reliance on EmA testing to select patients for biopsy will result in significant underdiagnosis.
authors.affiliation: Dept. of Gastroenterology, Altnagelvin Hospital, Londonderry, Northern Ireland.
authors.forename: W
authors.initials: W
authors.lastname: Dickey
authors.forename: D F
authors.initials: DF
authors.lastname: Hughes
authors.forename: S A
authors.initials: SA
authors.lastname: McMillan
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000276:immunology*; D001706:Biopsy; D002446:Celiac Disease / Q000175:diagnosis* / Q000178:diet therapy / Q000276:immunology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005903:Gliadin / Q000276:immunology*; D006801:Humans; D017098:IgA Deficiency; D007070:Immunoglobulin A / Q000097:blood*; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000276:immunology; D015995:Prevalence
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D005903:Gliadin