Patent ID: 7531362
Filing Date: 2009-05-12
Classification: G01N,Y10T

Abstract:
1. A method for determining the presence or absence of a target analyte in a fluid test sample, the method comprising the steps of: applying the fluid test sample to a reaction zone of a test unit, whereby the fluid test sample flows downwardly or vertically through the reaction zone, the reaction zone containing an immobilized capture reagent that binds the target analyte in the deposited fluid test sample to form a two-membered complex of a specific binding interaction; allowing the fluid test sample to flow downwardly or vertically through the reaction zone into an absorbent zone in vertical communication with the reaction zone, the absorbent zone comprising an absorbent material positioned underneath the reaction zone for facilitating the downward or vertical flow of the fluid test sample through the reaction zone so as to concentrate the two-membered complex in the reaction zone; affixing a post filter unit to the test unit, such that a label zone of the post-filter unit and the reaction zone of the test unit are proximally disposed, so as to be in transient fluid communication with one another to thereby allow direct downward or vertical fluid flow of a resolubilized dried indicator agent in the label zone to the reaction zone; applying a buffer reagent to the post-filter unit to resolubilize the dried indicator reagent after the fluid test sample is applied to the reaction zone and after the post-filter unit is affixed to the test unit; allowing the resolubilized indicator reagent to flow downwardly or vertically through the reaction zone and into the absorbent zone to bind with the two-membered complex concentrated in the reaction zone, with any unbound reactants being washed from the reaction zone into the absorbent zone; and removing the post-filter unit from the test unit subsequent to the application of the buffer reagent to the label zone and the binding of the resolubilized indicator reagent with the two-membered complex to observe a test result depicted by a presence or absence of a visually detectable signal on the reaction zone.