One or more embodiments are described directed to a method and system for concentrating components of a fluid circulated through a cell growth chamber such as a cell growth chamber. Accordingly, embodiments include methods and systems that utilize a tangential flow filter to concentrate components of a fluid that in embodiments includes expanded cells. In embodiments, a concentrated fluid component and a concentrated cell component are generated by flowing the fluid with expanded cells across a tangential flow filter. The concentrated cell component may be recirculated to the tangential flow filter to reach some desired concentration of cells. The concentrated fluid component may be collected to utilize cellular-produced constituents in the concentrated fluid component.