An effective control strategy is critical to ensure the safety, purity and potency of biopharmaceuticals. Appropriate analytical tools are needed to realize such goals by providing information on product quality at an early stage to help understanding and control of the manufacturing process. In this work, a fully automated, multi-capillary instrument is utilized for size-based separation and western blot analysis to provide an early readout on product quality in order to enable a more consistent manufacturing process. This approach aims at measuring two important qualities of a biopharmaceutical protein, titer and isoform distribution, in cell culture harvest samples. The acquired data for isoform distribution can then be used to predict the corresponding values of the final drug substance, and potentially provide information for remedy through timely adjustment of the downstream purification process, should the expected values fall out of the accepted range.