Patent ID: 6086748
Filing Date: 2000-07-11
Classification: G01N,Y10S

Abstract:
A method for detecting or quantifying an analyte in a test sample, comprising:providing a test device comprising an absorbent material, which absorbent material comprises:a contact portion at or proximate to a first end of said absorbent material; andan electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end;said electrochemical measurement portion comprising an indicator electrode portion and a reference electrode portion, wherein said indicator electrode portion and said reference electrode portion are segregated from one another on said absorbent material and are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said contact portion and said electrochemical measurement portion, wherein said liposome lysing portion is segregated from said contact portion and has a liposome lysing agent bound thereto, or said indicator electrode portion has a liposome lysing agent bound thereto;combining a binding material specific for the analyte with a conjugate of an analyte analog and liposomes and the test sample in an electrolyte mixture, wherein said liposomes comprise an electroactive marker;incubating the mixture for a time sufficient to permit competition between any analyte present in the test sample and the conjugate for the binding material;contacting the mixture with said contact portion of said absorbent material after said incubating;allowing the mixture to migrate from said contact portion through said electrochemical measurement portion of said absorbent material after said incubatin, wherein migration of aggregates of conjugate and binding material formed during said incubating is inhibited by said absorbent material, whereby said liposomes are lysed by said liposome lysing agent to release said marker, an electrical connection between said indicator and reference electrode portions is established, and a potential differential is established between said indicator electrode portion and said reference electrode portion;detecting the presence or amount of said potential differential between said indicator electrode portion and said reference electrode portion; andcorrelating the presence or amount of said potential differential with the presence or amount, respectively, of the analyte in the sample.