IMMUNOASSAY OF HIGH SENSITIVITY

PROBLEM TO BE SOLVED: To inexpensively perform measurement of high sensitivity in immunoassay using metal colloid as a colored label material, especially in an immunochromatographic measuring method. SOLUTION: The immunoassay is constituted so as to react an analyzing target substance with a reagent, which is immunologically reacted with the analyzing target substance, to detect a composite of both of them. Further, one of the analyzing target substance and the reagent is preliminarily labelled by a metal colloid particle obtained by supporting platinum colloid on palladium colloid to bring the composite into contact with a sensitizer solution containing metal ions to reduce metal ions on metal colloid particles to precipitate a metal to detect it. A sandwich method, especially immunochromatographic measuring method is preferable. COPYRIGHT: (C)2009,JPO&INPIT