Patent ID: 7524462

Claim:
An apparatus comprising: a first channel, wherein a fluid introduced to the apparatus flows through said first channel, wherein said first channel comprises: an upstream region; a tagging region downstream of said upstream region, wherein an analyte is tagged when said fluid flows through said tagging region by interacting with a tagging reagent present in the tagging region; a capture region downstream of said tagging region, wherein at least one tagged analyte is captured when said fluid flows through said capture region by binding to at least one analyte capture reagent immobilized in the capture region; a second channel communicating said upstream region of said first channel with said first channel intermediate said tagging region and capture region, wherein a portion of said fluid flows through said second channel and subsequently flows into said capture region of said first channel; and wherein said second channel comprises means for retarding flow rate, whereby fluid flowing through said tagging region flows into said capture region before said portion of said fluid flowing through said second channel flows into said capture region of said first channel.