optimization and application of quantitative in-house elisa for diagnosis of hbsag and its correlation with commercial elisa and molecular kits

Background: several studies have indicated the role of quantitative hepatitis b surface antigen (hbsag) evaluation in managing and prognosis of hepatitis b virus (hbv) infection. thus, quantitative evaluation of hbsag using cost-effective assays can be an important approach to managing hbv patients. objectives: this study aimed to set up and apply an in-house quantitative enzyme-linked immunosorbent assay (elisa) to evaluate hbsag in research and diagnosis. methods: new zealand white rabbits were immunized with hbsag. sera were collected 28 days after immunization, and polyclonal hbsab (antibody to hepatitis b surface antigen) were purified and evaluated. then, the in-house quantitative elisa was optimized. finally, the functional characteristics of the assay were evaluated using 200 plasma samples compared to commercial elisa and quantitative taqman real-time pcr. results: the assay has a limit of detection (lod) of 0.5 ng/ml with a specificity and sensitivity of 94% and 97%, respectively. the assay's highest coefficient of variation (cv) values for intra- and inter-assays were 7.23% and 8.59%, respectively. the correlation of the developed assay with commercial elisa was 0.987 (p-value = 0.024). the correlations of the developed assay and commercial elisa with quantitative taqman real-time pcr were 0.739 and 0.658, respectively (p-value = 0.017). conclusions: the developed assay has a suitable sensitivity and specificity. it is also reproducible and well-correlated with commercial assays. most importantly, it is cost-effective and, thus, can be used for detecting and quantifying hbsag in research and diagnosis.