Immunoassay method and immunoassay kit

Abstract

An immunoassay method comprising bringing an immobilized phase comprising, at different positions on a water-absorbable base material, at least two first immunity substances capable of specifically binding with at least two kinds of assay target substances selected from the group consisting of verotoxin-producing Escherichia coli, verotoxin and human hemoglobin contained in a test sample, into contact with a test sample and a liquid containing labeled immunity substances each comprising a second immunity substance that is labeled with colored particles and capable of binding with said assay target substance, thereby to form an assay target substance-labeled immunity substance complex and to bind said complex with respective first immunity substances at the immobilized phase. The immunoassay method, the immunoassay device and the immunoassay kit of the present invention enable easy and simultaneous analysis of O157 (VTEC), VT and Hb in a test sample, by adsorption of the assay target substances on an immobilized phase and evaluation of the developed color.

What is claimed is:  
     
         1 . An immunoassay method comprising bringing an immobilized phase comprising, at different positions on a water-absorbable base material, at least two first immunity substances capable of specifically binding with at least two kinds of assay target substances selected from the group consisting of verotoxin-producing  Escherichia coli,  verotoxin and human hemoglobin contained in a test sample, into contact with a test sample and a liquid containing labeled immunity substances each comprising a second immunity substance that is labeled with colored particles and capable of binding with said assay target substance, thereby to form an assay target substance-labeled immunity substance complex and to bind said complex with respective first immunity substances at the immobilized phase.  
     
     
         2 . The immunoassay method of  claim 1 , wherein the contact is made by flowing a mixture of the test sample and the liquid, so that it is absorbed from one end of the water-absorbable base material, thereby to bind said complex with the first immunity substance.  
     
     
         3 . The immunoassay method of  claim 1 , wherein the contact is made by flowing the test sample, so that it is absorbed from one end of the water-absorbable base material, thereby to bind the assay target substance with the first immunity substance, and then flowing the liquid to allow absorption thereof by the base material, thereby to bind said labeled immunity substance with the assay target substance.  
     
     
         4 . The immunoassay method of  claim 1 , wherein the contact is made by having the test sample absorbed halfway up to the immobilized phase, allowing the liquid to be absorbed from one end of the water-absorbable base material, thereby to form a complex of said labeled immunity substance and the assay target substance, and binding said complex with the first immunity substance at the immobilized phase.  
     
     
         5 . The immunoassay method of  claim 1 , wherein the contact is made by forming a label phase at a position halfway up to the immobilized phase, the label phase comprising the labeled immunity substance in such a manner that the labeled immunity substance can be released from the base material upon contact with water, allowing the test sample to be absorbed from one end of the water-absorbable base material, thereby to form a complex of said labeled immunity substance and the assay target substance, and binding said complex with the first immunity substance at the immobilized phase.  
     
     
         6 . An immunoassay device comprising an immobilized phase comprising plural first immunity substances each capable of specifically binding with an assay target substance immobilized on a water-absorbable base material, and a label phase comprising a labeled immunity substance comprising a second immunity substance that is labeled with colored particles and capable of binding with said assay target substance, in such a manner that the labeled immunity substance can be released from the base material upon contact with water, said immobilize phase comprising at least two first immunity substances capable of specifically binding with at least two kinds of assay target substances selected from the group consisting of verotoxin-producing  Escherichia coli,  verotoxin and human hemoglobin contained in a test sample, said first immunity substances being immobilized on different positions on the base material.  
     
     
         7 . An immunoassay kit comprising an immobilized phase comprising, on a water-absorbable base material, plural immobilized first immunity substances each capable of specifically binding with an assay target substance, and a liquid containing labeled immunity substances each comprising a second immunity substance that is labeled with colored particles and capable of binding with said assay target substance, said assay target substance being at least two kinds of assay target substances selected from the group consisting of verotoxin-producing  Escherichia coli,  verotoxin and human hemoglobin.