Patent ID: 7521196
Filing Date: 2009-04-21
Classification: B01L,G01N,Y10S,Y10T

Abstract:
1. A method for detecting an analyte in a sample comprising: delivering a buffer to a test strip to prewet the test strip, wherein said test strip comprises (i) a buffer additional zone, (ii) a sample addition zone, (iii) one or more test zones positioned between the buffer addition zone and the sample addition zone, wherein at least one of the test zones includes a first analyte binding agent immobilized therein which binds to analyte in the sample, and (iv) a terminal buffer flow zone positioned between the one or more test zones and the sample addition zone, and (v) an absorbent zone positioned relative to the buffer addition zone having absorbent properties such that when a predetermined volume of buffer is added to the buffer addition zone, the buffer diffuses through the one or more test zones into the terminal buffer flow zone and the absorbent properties of the absorbent zone cause the buffer to be drawn backward across the test zones toward the buffer addition zone and into the absorbent zone; delivering a sample to the sample addition zone of the test strip, delivery of the sample causes analyte in the sample and a competitive agent to diffuse past the terminal buffer flow zone to the one or more test zones and to the absorbent zone, after the buffer diffuses past the one or more test zones, the competitive agent competes with the analyte for binding to the first analyte binding agent immobilized in the test zones; and detecting the competitive agent immobilized in the test zone.