FCS Express can calculate the absolute concentration of the cells in a sample. FCS Express does so by automatically calculating the volume of the sample that was used during acquisition. The volume can be calculated by a) using beads that were present in the sample tube at a known concentration, b) using the sample flow rate and acquisition time, or c) using the volume keyword from FCS 3.1 files, or the equivalent in Amnis DAF files, if available. FCS Express can display the concentration as a one time calculation, in a statistics table, or as a token.

 

To begin, we will set up the bead gates.