QUANTITATIVE DETECTION OF ANALYTES ON IMMUNOCHROMATOGRAPHIC STRIPS

Disclosed is an improved method for determining the concentration of analyte in a test fluid by immunochroma-tography techniques which involves quantitatively deter-mining the signals from captured analyte/labeled binding partner complex by instrumental means, e.g. reflectance spectrometry. In a preferred embodiment, a reflectance reading is determined for the captured complex and uncom-plexed labeled binding partner which is captured in a separate zone of the immunochromatographic strip and the ratio of these reflectances is used to provide additional quantitation to the assay method.