The purpose of this study is to evaluate the effectiveness of antitissue transglutaminase (atTG) chemiluminescence immunoassay (CLIA) methods with traditional enzyme-linked immunosorbent assay (ELISA) methods in monitoring celiac children after they begin a gluten-free diet (GFD). Celiac children diagnosed at our center between 2005 and 2016 were divided into two groups based on the blood test (ELISA vs CLIA) used for atTG monitoring, and the percentage of reduction and time to normalization of atTG on GFD were compared. At 30 months’ follow-up, the rate of normalization of atTG levels among 260 included children was 86 percent in the ELISA group and 70 percent in the CLIA group, respectively. The median duration to normalization in the ELISA and CLIA groups was 11.7 and 14.7 months, respectively. Marsh score at diagnosis had no effect on time to atTG normalization, while older age at diagnosis and higher baseline atTG predicted a longer time to normalization.

The proportion and time of atTG normalization in celiac children on GFD should be evaluated based on the assay used: at 30 months’ follow-up, children tested by CLIA are less likely to normalize atTG levels than those tested by ELISA. Regardless of the test used, younger age at diagnosis and lower baseline atTG are predictors of quicker atTG normalization.