title: An electrochemical immunoassay for the screening of celiac disease in saliva samples.
abstract: A highly sensitive electrochemical immunoassay for the initial diagnosis of celiac disease (CD) in saliva samples that overcomes the problems related to its high viscosity and to the low concentration of anti-transglutaminase antigen (tTG) IgA in this medium has been developed for the first time. The system uses magnetic beads (MBs) covered with tTG, which reacts with the anti-tTG IgA antibodies present in positive saliva samples. An anti-human IgA, conjugated with alkaline phosphate (AP) enzyme, was used as the label and a strip of eight magnetized screen-printed electrodes as the electrochemical transducer. In particular, two different immunoassay approaches were optimized and blindly compared to analyze a large number of saliva samples, whose anti-tTG IgA levels were independently determined by the radioimmunoassay (RIA) method. The obtained results, expressed as Ab index, were used to perform a diagnostic test evaluation through the construction of receiver operating characteristic (ROC) curves. The approach, involving a pre-incubation between the anti-human IgA-AP and saliva samples prior to the addition of MBs-tTG, showed a cutoff of 0.022 with 95% clinical sensitivity and 96% clinical specificity. The area under the ROC curve is equal to 1, a result that classifies our test as "perfect." This study demonstrates that it is possible to perform the screening of CD with a rapid, simple, inexpensive, and sensitive method able to detect anti-tTG antibodies in saliva samples, which are easily obtained by non-invasive techniques. This aspect is of fundamental importance to screen a large number of subjects, especially in the pediatric age.
authors.affiliation: Department of Chemical Science and Technologies, Tor Vergata University, Via della Ricerca Scientifica, 00133, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Adornetto
authors.forename: Laura
authors.initials: L
authors.lastname: Fabiani
authors.forename: Giulia
authors.initials: G
authors.lastname: Volpe
authors.forename: Alessia
authors.initials: A
authors.lastname: De Stefano
authors.forename: Sonia
authors.initials: S
authors.lastname: Martini
authors.forename: Raffaella
authors.initials: R
authors.lastname: Nenna
authors.forename: Federica
authors.initials: F
authors.lastname: Lucantoni
authors.forename: Margherita
authors.initials: M
authors.lastname: Bonamico
authors.forename: Claudio
authors.initials: C
authors.lastname: Tiberti
authors.forename: Danila
authors.initials: D
authors.lastname: Moscone
mesh_terms: D002446:Celiac Disease / Q000175:diagnosis* / Q000378:metabolism*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D008403:Mass Screening / Q000295:instrumentation*; D015203:Reproducibility of Results; D012463:Saliva / Q000378:metabolism*; D012680:Sensitivity and Specificity