Patent ID: 6979576

Claim:
A method for determining the presence or absence of Streptococcus Group A antigen in a sample, comprising: (a) providing a lateral flow immunochromatographic device comprising a sample receiving region of porous material in liquid flow contact with a separate detection region of porous material, wherein said detection region comprises a mobile labeling reagent at a discrete labeling situs and an immobilized capture reagent at a discrete capture situs; and wherein said labeling reagent is a detectable label coupled to a binder which specifically binds to said antigen to form a labeled complex and said capture reagent specifically binds to said antigen or to said labeled complex; (b) providing an assay chamber which is separate from the lateral flow immunochromatographic device; (c) extracting said antigen from said sample with a liquid extraction solution comprising one or two extraction reagents in said assay chamber, wherein said one extraction reagent is added to the assay chamber, to form a liquid extract, or wherein said two extraction reagents are added to said assay chamber in any order, to form a liquid extract; (d) inserting said sample receiving region of said lateral flow immunochromatographic device into said assay chamber and contacting said liquid extract whereby said liquid extract flows through said labeling situs and then through said capture situs, without further addition of reagents or manipulation of said sample; and (e) determining the presence or absence of said antigen in said sample by detecting the presence or absence of said detectable label at said capture situs.