The study included samples contributed by investigators within the North American Celiac Disease Consortium, including Dr. Susan Neuhausen at UC Irvine (now at City of Hope), Dr. Joe Murray at the Mayo Clinic, Dr. Alesio Fasano at the University of Maryland Celiac Disease Center, and Dr. Peter Green at Columbia University. The resources from the four sites were similar in that they used the same serological tests and collected similar questionnaire data. To be considered a celiac case, the individual must have tested serologically positive for IgA tTG and/or IgA EMA and/or had a positive small intestinal biopsy. All of the subjects from the Mayo Clinic and greater than 90% of the subjects from UC Irvine/City of Hope and Columbia University were biopsied. For those with serology only, using sequential testing of IgA ttG followed by IgA EMA testing results in net specificity rates of virtually 100% making it practical to accurately identify those with celiac disease on the basis of serology alone [12], [13].
