Validation of a new immunoblot assay for the diagnosis of Helicobacter pylori in the Asian population

Background: Performance of commercial serological tests for Helicobacter py lori varies in different populations, largely due to strain heterogeneity a nd variations in antigenic preparations. Currently available serology tests often show sub-optimal accuracy when used for Asian patients. Aim: This study evaluated a recombinant antigen-based immunoblot for the di agnosis of H. pylori infection in Chinese patients, and compared it with a conventional ELISA test. Methods: Dyspeptic patients referred for diagnostic endoscopy were recruite d. The gold standard for H. pylori infection was based on two or more posit ive results among rapid urease test, histology and C-13-urea breath test. S erological diagnosis of H. pylori infection was conducted by an ELISA test (pylori DTect; Diagnostic Technology) and an immunoblotting against a novel recombinant antigen (C1S; Genelab), which was constructed by immunological screening of the genomic DNA library of H. pylori. Results: A total of 87 patients were evaluated and H. pylori infection was diagnosed in 40 (46%) by the reference tests. The sensitivities of the ELIS A and immunoblot were 80% (95% CI: 64-91%) and 90% (95% CI: 76-97%), whilst the specificities were 96% (95% CI: 86-96%) and 87% (95% CI: 74-95%), resp ectively. The respective likelihood ratios of the two tests were 18.6 and 7 .0. Conclusions: Satisfactory performance is obtained by the use of the new rec ombinant antigen-based immunoblot for diagnosing H. pylori infection in Chi nese patients.