Patent ID: 7773790

Claim:
A method for detecting the presence of at least a first target analyte in a test spot, comprising: acquiring multiple images of a test spot and a control spot on a substrate having a plurality of spots containing specific binding complements to one or more target analytes, the multiple images being taken with different amounts of exposure time, wherein the test spot comprises metallic nanoparticles complexed to specific binding complements in the presence of at least a first target analyte, and wherein the control spot comprises metallic nanoparticles, with or without signal amplification, complexed to specific binding complements in the presence of at least a second target analyte; performing regression analysis on portions of the acquired multiple images of the test spot and the control spot using a processor so as to generate functions of an amount of exposure time versus intensity of the test spot and intensity of the control spot; selecting one of the different amounts of exposure time; using the generated functions to determine an intensity of the test spot at the selected amount of exposure time and an intensity of the control spot at the selected amount of exposure time; and determining the presence of metallic nanoparticle complexes in the test spot by comparing the intensity of the test spot with the intensity of the control spot at the selected amount of exposure time, wherein the presence of the metallic nanoparticle complexes in the test spot indicates presence of the at least a first target analyte in the test spot.