Development of a High-sensitivity Detection Device for Hepatitis B Virus Surface Antigen in Saliva

According to the World Health Organization (WHO), two billion people are infected with hepatitis B virus (HBV). Among infectious diseases, viral hepatitis has been proposed as a target for global elimination. Currently, although blood-based examination is common, an alternative assay using saliva has attracted attention as a simple diagnostic method. However, many issues need to be overcome to facilitate the use of this method, such as sensitivity of the diagnostic method and stability of the sample. Therefore, we have developed a new testing method for HBV surface layer (HBs) antigen using immunochromatography, and have evaluated its effectiveness.

Comparison of the detection sensitivity of the conventional immunochromatography method with that of the newly developed immunochromatography method revealed that the latter showed a much higher sensitivity. Therefore, we collected blood and saliva samples from 70 HBs antigen-positive subjects and 100 HBs antigen-negative subjects in hospital and examined these samples using the newly developed immunochromatographic test. The positive and negative rates of blood and saliva of the 70 HBs antigen-positive subjects and the 100 HBs antigen-negative subjects were found to be completely consistent.

Thus, the high sensitivity of the newly developed immunochromatographic test strongly suggests the clinical applicability of saliva as a clinical sample. In the near future, we plan to clarify the feasibility of this new method for implementation in various medical facilities and survey applications, with the goal of developing a wide range of clinical tests to detect HBV.