Patent ID: 8586347

Claim:
A system for performing an assay on a sample to determine presence or absence of a target analyte in the sample, the system comprising: a cartridge having: (a) planar waveguide with a planar surface and a plurality of capture molecules bound thereto, (b) refractive volume for optically coupling a light beam to the planar waveguide, the refractive volume refracting the light beam such that all of the light beam focuses at a non-zero, internal propagation angle at the planar surface, and (c) sample chamber for containing the sample in contact with the plurality of capture molecules; and a reader instrument having: (a) light source for delivering the light beam parallel to the planar surface, and offset from the planar waveguide when incident on the refractive volume, (b) detector for detecting a light signal from a portion of the planar surface on which the plurality of capture molecules is bound, (c) analysis module for receiving and analyzing the light signal from the detector, and (d) a beam homogenizer.