Product concentration is likely the most critical parameter to monitor on a routine basis during large-scale manufacturing of recombinant proteins.  For instance, determining the best time frame for beginning downstream processing of therapeutic antibodies can influence the success of a manufacturing batch.  Knowing when to begin the downstream cycle can limit problems with reduced yields due to premature harvesting or prevent degradation of product which remains too long in the bioreactor.  Since ELISA monitoring is labor intensive and takes many hours for results, a more rapid technique, such as LamdaGen's label-free LSPR, offers significant advantages in monitoring the process in real-time (product concentration in the bioreactor) and can be implemented on-line or at-line.  LSPR can also be used to validate product specifications through characterization assays of biotherapeutic-target binding events and immunogenicity assays to verify safety.  Batch differences can easily be identified by monitoring binding interaction profiles for every batch produced.