Anti-CMV immunoglobulin has been proven and marketed; however, using currently commercial available kits to screen the high titer anti-CMV IgG plasma has been expensive and challenge due to the poor correlation between results obtained from screening kit and that of the cell-base neutralization assay which is considered to be most relevant assay. However, cultivation of CMC virus is a very tedious and slow process, therefore, it is non-practical to use neutralizing assay for screening plasma sample. With these short comings in mind, we are collaborating with Professor Kao at Clinical Virology Laboratory of Department of Laboratory Medicine from National Taiwan University Hospital to develop a new assay to improve assay specificity. By using recombinant DNA technology, several viral surface antigens has been selected and expressed by Pichia pastoris expression system. Antigens show high specificity will then be selected for further development.