Farideh Kamarehei - Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
Alireza Khabiri - Diagnostic Biotechnology Unit, Research and Production Complex, Pasteur Institute of Iran, Tehran, Iran
Massoud Saidijam - Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
Meysam Soleimani - Department of Pharmaceutical Biotechnology, Hamadan University of Medical Sciences, Hamadan, Iran
Mohammad Yousef Alikhani - Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran

Introduction and Objectives: Helicobacter pylori infection as the worldwide problem is related to many gastrointestinal disorders such as gastritis, gastric cancer, non-ulcer disease, peptic ulcer disease and duodenal ulcer. Materials and Methods: We produced and purified recombinant CagA and NapA antigens in Escherichia coli and extracted their antibodies from a panel of positive sera specimens. We designed a novel enzyme linked immunoassay direct method in combination with the whole cell for the qualitative and quantitative detection of Helicobacter pylori antigens in human stool. Assay performance was evaluated by histopathology staining and urease activity. Results: The sensitivity and specificity of assay was determined as 91.7 [95% confidence interval: 89.3-95.6%] and 93.1% [95% CI: 91.2-96.4%], respectively. Novel ELISA exhibits enhanced sensitivity and specificity of Helicobacter pylori detection in comparison with another commercially available kit. Conclusion: Combination of the recombinant antigens and whole cell of Helicobacter pylori in immunoassay designing is a new approach about early diagnosis, treatment and fallowing up of the Helicobacter pylori infected patients, especially in peptic cancer cases.

CagA protein, Helicobacter pylori, Neutrophil activating protein A, Enzyme-linked immunosorbent assay.