How does one make a diagnosis of celiac disease?
Celiac disease is a common cause of chronic fatty diarrhea, but may present without diarrhea. The population prevalence in the United States is estimated to be just less than 1%. Serologic testing for immunoglobulin A (IgA) antibodies against tissue transglutaminase is the preferred noninvasive test, but small bowel mucosal biopsy is the definitive test. If serologic testing is done, IgA levels should be measured because 10% of patients with celiac disease may have IgA deficiency, which would produce a false-negative test serologic result