Evaluation of the Usefulness of a Serological Test for Diagnosis of Celiac Disease Simultaneously Detecting Specific Antibodies and Total IgA.

The diagnosis of celiac disease (CD) at the first diagnostic step requires the detection of specific class A antibodies to tissue transglutaminase type-2 (TG2 IgA) and the measurement of total immunoglobulin A (tIgA) to exclude IgA deficiency. The aim of the study was to evaluate the new quantitative immunoassay panel allowing for the detection of celiac-specific antibodies with the simultaneous determination of tIgA from the same sample of blood at one time. This retrospective study included 104 pediatric patients divided into groups with recognized CD and IgA deficiency (n = 20; 19%), immunocompetent children with CD (n = 28; 27%), children with IgA deficiency and without CD (n = 28; 27%), and the control group of immunocompetent children without CD (n = 28; 27%). Intestinal biopsy with histopathological evaluation (except five patients with CD who were diagnosed without biopsy) and measurement of reference celiac specific antibodies were performed in all children. Multiparametric quantitative immunoassay Polycheck Celiac IgA plus total IgA test was used to evaluate its usefulness in CD screening and IgA deficiency diagnosis. The statistical analysis showed the high sensitivity and specificity of both TG2 IgA and tIgA on the multiparametric panel (sensitivity 96% and 100%; specificity 100% and 79%, respectively). The accuracy and area under the ROC curve for tIgA were 0.904 and 0.955, while for TG2 IgA they were 0.982 and 1.000, respectively. Although the sensitivity of IgA antibodies against deaminated gliadin peptides was low (20%), the specificity reached 100%. The study showed that Polycheck Celiac IgA plus total IgA test is a specific and sensitive tool for simultaneous serological CD screening and recognition of IgA deficiency.