Microfluidic assay devices

An assay device for detecting the presence or concentration of an analyte within a fluid test sample, said assay comprising:

• an input channel;
• a substantially circular analysis zone in fluid communication with said input channel, said analysis zone defining a periphery, wherein said analysis zone serves as a location for detecting the analyte;
• a plurality of wicking channels extending radially from the periphery of said analysis zone, wherein said wicking channels have an aspect ratio of from about 0.1 to about 10 and a cross-sectional area of less than about 20 square millimeters;
• and
• an overflow zone that is in fluid communication with said plurality of wicking channels, wherein the assay device is configured so that the fluid test sample is capable of flowing through said input channel and said analysis zone primarily via capillary action.

A method for performing an assay, said method comprising:

• introducing into an input channel a fluid test sample suspected of containing an analyte;
• allowing the fluid test sample to flow via capillary action from said input channel to an analysis zone that defines a periphery;
• detecting the presence or absence of the analyte;
• and
• drawing the fluid test sample from the analysis zone using a plurality of microfluidic wicking channels, said wicking channels extending outwardly from the periphery of said analysis zone.