Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Hepatitis C virus.

Hepatitis C virus (HCV) is a major public health problem and a leading cause of chronic liver disease. An estimated 180 million people are infected worldwide. In this study, we developed a loop-mediated isothermal amplification (LAMP) assay for rapid detection of HCV genomic RNA and compared the sensitivity of LAMP with nested-PCR. A total of 30 blood samples from HCV-infected patients were analyzed with six primers targeting conserved sequences of the HCV 5'UTR within 70 min, under isothermal conditions at 62 °C. Then, visualized by gel electrophoresis with ethidium bromide staining and detected by the naked-eye after adding SYBR Green I. All samples positive for HCV by nested PCR were confirmed by LAMP method. When visualized by gel electrophoresis and ethidium bromide staining, the HCV LAMP assay products appeared in a ladder pattern, with many bands of different sizes. The HCV LAMP product could also be detected by the naked-eye after adding SYBR Green I to the reaction tube and observing a color change from orange to green in positive samples. The HCV LAMP had the same sensitivity as a nested-PCR assay, the detection limit for the both systems were found to be 10 copies/mL of HCV RNA. The LAMP assay reported here is superior for rapid amplification, simple operation, and easy detection and will be useful for rapid and reliable clinical diagnosis of HCV in areas with limited resources, such as developing countries.