One major goal of biopharmaceutical production is to reduce the development time until registration by increasing the specific productivity and to advance product quality. In the past big efforts were made to increase the volumetric yield by optimization in fermentation and downstream technologies. However, therapeutics gets more complex, thus not only the production yield is important but also product quality. Consequently, biopharmaceutical producer are searching for tools and methods to monitor the product quality very early to select efficient candidates for production. This book will give you an overview about suitable methods to analyze and characterize glycoproteins using the example of a fusion protein rhEpo-Fc. It comprises the establishment and validation of a microtiterplate assay to determine terminal sialic acid and a technique for quantitative isoform pattern analysis directly performed in serum-free culture supernatant. N-linked oligosaccharides were released enzymatically from the fusion protein as well as from the fusion partners separately and analyzed by normal-phase HPLC.