Method For Analyzing Fluorescent Particles in an Immunoassay

A method of making sensitive measurements of quantity of target analytes dissolved in liquid and attached to microsphere particles wherein the analyte coated particles are labeled with a fluorescent marker. The solution is placed in a light transparent container having a planar bottom and the particles allowed to settle. Illuminating a sample with a light source and creating a camera image. Evaluating the image for presence of particles within the sample and focus sharpness. Repositioning an objective lens or sample as required. Illuminating a portion of one particle within the sample with a light source having a specified wavelength and measuring the scattered light and emitted fluorescent light utilizing a confocal apparatus with at least one photodetector having specified photosensitive characteristics. Measurement of light characteristics includes laser scanning conformal cytometer. The method includes using a mathematical function derived standard curve to infer the concentration of the analyte.