Because the development of industrial cell culture processes for production of recombinant proteins seeks high efficiency, reproducibility and predictability, it is important to have access accurate analytical tools. Although established analytical methods deliver useful data, they are incomplete because they only partially address the cellular metabolic state and also because no predictions can be made.

This paper discusses the process used to establish and evaluate an assay for rapid and reliable online measurement of intracellular ATP (adenoside-5′-triphosphate) to monitor the physiological state of cells in combination with other parameters (cell number, viability, and glucose consumption).