A method for rapid collection and assay of oral fluids is disclosed. The method comprising the steps of: (a) placing an assay device into an oral cavity, (b) removing said assay device from said oral cavity; and (c) determining the presence or absence of at least one analyte. The assay device used in the method comprises: (i) an assay portion housing an immunochrornatographic lateral flow assay strip, the lateral flow assay strip containing at least one reagent selected from an antigen and an antibody that is used to detect one of the presence or absence of at least one analyte in a fluid; (ii) a neck portion extending from the assay portion, the neck portion forming a channel for delivery of fluid to said assay strip and the channel being defined by a first, narrow part proximal to the assay portion and a second part including an opening for receiving the oral fluid, wherein the second part includes a channel width that is substantially wider than the channel width at the narrow end; (iii) a collection strip in fluid communication with the lateral flow assay strip, the collection strip having a first portion disposed within the channel and a second portion protruding outwardly from the neck portion opening; and (iv) a blocking strip coupled between and in flow communication with the lateral flow assay strip and the collection strip.