Patent ID: 7723127

Claim:
A method of performing a competitive assay for a target analyte in a sample which may contain a concentration of the target analyte, comprising the steps of: a) combining in a vessel a first volume containing a first quantity of said sample and a first quantity of dilution buffer, a first reagent volume containing a known concentration of the target analyte conjugated to a an enzyme, and a second reagent volume containing one or more substrates upon which said enzyme acts and receptors having affinity for the target analyte, wherein said target analyte conjugated to said enzyme binds to said receptors; b) thermally incubating said vessel for a first time interval; c) adding a second volume containing a second quantity of said sample and a second quantity of dilution buffer to said vessel, whereby a ratio of an amount of said sample in said second volume to the amount of said sample in said first volume is equal to a prescribed dilution factor; d) thermally incubating said vessel for a second time interval, during which time an assay signal generated by the action of said enzyme on said one or more substrates is measured and a rate of change of said assay signal is determined, wherein the binding of said target analyte conjugated to said enzyme with said receptors decreases said assay signal, and wherein said signal is measured prior to achieving chemical equilibrium; and e) relating said rate of change of said assay signal to a concentration of said target analyte in said sample using a pre-determined dose-response curve.