Establishment and characterization of noro-VLP measurement by digital ELISA

of 0.9984. Analysis of samples containing 5 ng per mL noro-VLP confirmed inter-assay variation of 4.5%, and intra-assay variation of 2.5%. Comparison of the two systems using the same calibrant for unpurified and fractionated noro-VLPs revealed that the quantitative values for unpurified noro-VLPs were the same, whereas those for fractionated noro-VLPs were dramatically different. Our findings indicate that the reactivity to various components in the noro-VLP solution was altered depending on the different antibodies. Furthermore, our study highlights the importance of using appropriate calibrants, which contain the same ratio of components as the noro-VLP analyte, to afford accurate measurements.