Abstract: The present invention relates to an immunoassay and diagnostic reagent for malaria by using antigens of malarial Protozoa. More preferably, the present invention relates to an immunoassay and diagnostic reagent for malaria which detect malaria-specific antibodies in blood by using Merozoite Surface Protein of Plasmodium vivax. The immunoassay and diagnostic reagent detecting malaria-specific antibodies in blood according to the present invention have high specificity and sensitivity and are useful in diagnosing a type of malaria where latent period is long and number of Protozoa in blood if few. Also, the present invention relates to a preparation method of the surface protein of malarial Protozoa using yeast or E. Coli. Preferably, the present invention provides an expression vector comprising genes of Merozoite Surface Protein of Plasmodium Vivax and histidine residues, as well as transformants transformed with the expression vector.

Abstract: The present invention relates to diagnostic reagents for antibody against hepatitis B surface antigen and for antibody against hepatitis B virus using a sandwich immunoassay as a quantitative or qualitative analysis method for antibody against hepatitis B surface antigen and for antibody against hepatitis B virus, characterized in that each diagnostic reagent comprises a pair of hepatitis B surface antigens which are different each other and composed of primary antigen immobilized on a solid support and secondary antigen conjugated to a marker. Also, the present invention relates to preparation methods thereof. Further, the present invention relates to diagnostic methods for antibody against hepatitis B surface antigen and for antibody against hepatitis B virus.