| abstract |
Disclosed are assay systems, kits, and methods for performing an assay which determines the presence or quantity of an analyte in a fluid sample by detecting binding of the analyte to at least one immobilized analyte capture reagent and washing unbound material from the immobilized analyte capture reagent. An elongated solid phase flow matrix includes: (i) a first region adapted for receipt of the fluid sample, (ii) a second region at which the analyte capture reagent is immobilized, (iii) a third region for application of a liquid wash and/or detector reagent capable of removing unbound substances from the second region; and (iv) an absorbent reservoir of high volume capacity. The second region is positioned between the first region and the third region and between the absorbent reservoir and the third region. The device also includes means to detect analyte bound at the second region. The fluid sample flows by capillary action initially along the elongated flow matrix in one direction toward and through the second region, and subsequently, liquid wash and/or detector reagent flows along the matrix in a second direction opposite the first direction, through the second region, and into the absorbent reservoir, drawing unbound substances with it. |