Does celiac sero-diagnosis always require a tertiary referral centre confirmation? Our experience in Marche region

Abstract

Background: Evaluation of celiac autoantibodies is a crucial step in the diagnostic algorithm of celiac disease (CD). The need of intestinal biopsy mainly relies on TTG IgA levels (with biopsy still needed if levels are less than 10 times the ULN, subdiagnostic levels [SDLs]). Aim: To evaluate the agreement of serological CD markers between different regional peripheral laboratories (PLs) and our referral regional laboratory (RL) in Salesi Children’s Hospital (Ancona). Methods: Childrenwith a final diagnosis of CD confirmed in our centre (May 2014–April 2015) and a previous (within 1 month) serological evaluation (TTG IgA and DGP IgG) performed in one PLs were included. Levels (times the ULN) of TTG IgA and DGP IgGwere compared between the RL and the PLs. Results: Forty-one subjects (mean age: 6.2 years) with a diagnosis of CD were included. Overall the RL confirmed abnormal CD antibodies detected in PLs in 100% of patients. A small proportion were discordant in TTG IgA levels: 10% with SDLs detected in a PL had diagnostic levels in the RL, while 17% with>10 times the ULN in a PLwere found to have SDLs in the RL, requiring confirmation by biopsy. Bland Altaman analysis suggested that the levels of TTG IgA in the RL was on average 4.8 times higher (SD 14.8) than the levels in the PLs with wide limits of agreement (95% limit of agreement: −33.83 to 24.20 times). Conclusion: In our regional setting the determination of serological CDmarkers in a PLswas overall reliable andwe found a good correlationwithmeasurement in the RL. Howeverwe still consider the confirmation in our RL a fundamental step in the diagnostic process.