Patent ID: 8652407

Claim:
A self-contained assay device for detecting analyte(s) in a specimen comprising: a first housing having a bottom and a raised wall; a button tower centrally secured to the bottom of the first housing, the button tower including: a base having a spring-loaded ram pin; a button engaging a trigger to retract the ram pin within the base member, the button having a plurality of cut-out portions; a membrane housing block fixedly fit in a position on the raised wall of the first housing and having an opening configured to receive a liquid specimen, the membrane housing block including a porous membrane on a bottom portion, a liquid inlet orifice in a position facing the button tower, and a liquid-tight seal surrounding the opening; an absorbent blotter located adjacent to the bottom of the first housing, the absorbent blotter having a raised portion located in a position under the membrane housing block; a blotter barrier plate located on a surface of the blotter opposite the bottom of the first housing; a second housing adapted to be fixedly fit in the first housing, the second housing including: a top surface having a handle portion and a center hole for receiving the button; a rim portion defining an outer end wall and a plurality of chambers, wherein each chamber has a first opening located at the outer end wall for communicating with the membrane housing block and a second opening located at an inner portion of the chamber opposite the first opening, wherein each chamber has at least one cam-shaped surface adjacent to the second opening, and wherein each chamber has a cylinder and piston assembly secured to the chamber by a coil-over spring, the cylinder and piston assembly retaining a reagent or wash solution, wherein the piston includes a channel comprising a vented set screw, a ball bearing, and a spring acting on the ball bearing to seal an outer end of the channel to provide a liquid-tight reservoir for the reagent or wash solution, wherein, when the button is depressed, the second housing is able to rotate relative to the membrane housing block thus causing the ram pin to engage one of the cam surfaces of the rim portion of the second housing to contain the ram pin until it reaches the second opening in one of the chambers thus causing the ram pin to thrust into the cylinder to move the cylinder and piston assembly, opposite the force of the coil-over spring, against the liquid inlet orifice on the membrane housing block thus moving the ball bearing to break the seal and allow the reagent or wash solution to escape into the membrane housing block and onto the membrane.