"19% of pediatric celiac disease patients treated with a gluten-free diet had persistent enteropathy. At the time of the repeat biopsy tTG was elevated in 43% of cases with persistent enteropathy and 32% of cases in which there was mucosal recovery. Overall the positive predictive value of the autoantibody tTG was 25% and the negative predictive value was 83% in patients on a gluten-free diet for a median of 2.4 years."xsd:string