Patent ID: 6916661

Claim:
A method of determining a concentration or a relative concentration of an analyte in a multiplicity of samples of different origins using an instrument which separates and classifies microparticles and measures results of a bimolecular reaction between an analyte and a reagent, comprising the steps of: (a) providing a population of microparticles which includes distinct subpopulations of microparticles, wherein each of the microparticles of the population comprises a polymeric microparticle and a plurality of nanoparticles coupled to the polymeric microparticle, wherein each of the distinct subpopulations is uniquely labeled with two or more labels having two or more characteristics detectable by the instrument, wherein substantially all of the microparticles of the subpopulations are attached to the reagent which reacts with the analyte in the bimolecular reaction, and wherein the results of the bimolecular reaction are measurable by the instrument; (b) exposing each of the multiplicity of samples to one of the distinct subpopulations of microparticles to form a plurality of mixtures; (c) incubating the plurality of mixtures until the bimolecular reaction is substantially complete; (d) combining the plurality of mixtures to form a combined mixture; (e) passing the combined mixture through the instrument; (f) identifying the subpopulation of said each of the microparticles using the two or more characteristics; (g) measuring the results of the reagent and analyte bimolecular reaction of said each of the microparticles; and (h) calculating the concentration or relative concentration of the analyte in each of the multiplicity of samples.