A method to determine the presence or absence of Streptococcus Group A antigen in a sample, comprising the following steps: extracting the antigen from the sample in an assay chamber with two or less extraction reagents, wherein the two reagents may be added to the assay chamber in no particular sequence; introducing a lateral flow immunochromatographic assay device into the extraction reagents containing the extracted antigen without further addition of reagents or manipulation of the sample; forming an antigen-indicator labeling reagent complex; and determining the presence or absence of the antigen in the sample by the presence or absence of a signal formed by the binding of the antigen-indicator labeling reagent complex to an indicator capture reagent specific for said antigen-indicator labeling reagent complex.