Luminex Assay Principle

The sample is added to a mixture of color-coded beads, pre-coated with analyte-specific capture antibodies. The antibodies bind to the analytes of interest. Biotinylated detection antibodies specific to the analytes of interest are added and form an antibody-antigen sandwich. Phycoerythrin (PE)-conjugated streptavidin is added. It binds to the biotinylated detection antibodies.
Polystyrene beads are read on a dual-laser flow-based detection instrument, such as the Luminex® 100, Luminex 200 or Bio-Rad® Bio-Plex® analyzer. One laser classifies the bead and determines the analyte that is being detected. The second laser determines the magnitude of the PE-derived signal, which is in direct proportion to the amount of analyte bound. In addition to the Luminex 100, Luminex 200 or Bio-Rad Bio-Plex dual-laser, flow-based analyzers, magnetic beads can be read using the Luminex MAGPIX® Analyzer. A magnet in the MAGPIX analyzer captures and holds the magnetic beads in a monolayer, while two spectrally distinct light-emitting diodes (LEDs) illuminate the beads. One LED identifies the analyte that is being detected and, the second LED determines the magnitude of the PE-derived signal. Each well is imaged with a CCD camera.