Use of the anti-endomysial antibody test to diagnose coeliac disease in clinical practice.Clin Lab. 2002; 48(5-6):319-25.CL
Guidelines suggest that duodenal biopsies should be taken in patients with iron deficiency anaemia.
To examine anti-endomysial antibody (anti-EMA) and duodenal biopsy testing in Portsmouth, UK. To evaluate if the current pathology workload can be reduced by anti-EMA replacing some duodenal biopsies. To determine to what extent doctors in Portsmouth are confirming a positive anti-EMA test by small bowel biopsy.
Patients' records were examined firstly from whom duodenal biopsies were taken between April 1999 and September 2000, and secondly who had anti-EMA tested between December 1999 and September 2000.
Queen Alexandra Hospital, UK. District General Hospital. Medical Outpatients Department.
In the first group, of 354 patients undergoing duodenal biopsy, 108 patients had anti-EMA tested. Of these 108 patients, 25 had positive IgA anti-EMA and 83 had negative IgA anti-EMA. Of these 83 patients who had negative IgA EMA, 8 patients had a duodenal biopsy suggestive of Coeliac Disease. 4 of these 8 patients were on gluten free diets at the time of anti-EMA testing so were excluded. 1 of the 4 patients who had a duodenal biopsy indicative of Coeliac Disease had a positive IgG anti-EMA despite negative IgA anti-EMA. Therefore 3 false negative IgG anti-EMA were ultimately identified giving a sensitivity of 89% and a specificity of 100%. On follow up one has subsequently been found to have T-cell lymphoma; if this patient is taken into account the sensitivity of anti-EMA increases to 93%. In the second group; 1450 patients had anti-EMA tested. Of the 67 positive anti-EMA tests in this group only 12 had a duodenal biopsy.
Many patients who have been tested for anti-EMA are not offered duodenal biopsy in Portsmouth despite current British Society of Gastroenterology (BSG) guidelines, although it should be noted that the BSG guidelines on iron-deficiency anaemia recommend using anti-EMA without histology to exclude Coeliac Disease in menstruating women (biopsy would still be recommended if anti-EMA were positive). Our study has found a high sensitivity and specificity of anti-EMA; there may therefore be some circumstances where duodenal biopsy is unnecessary in the investigation of Coeliac Disease. Patients with suspected Coeliac Disease and negative anti-EMA should be evaluated for other causes of villous atrophy.