How are the cell counts and viabilities of DTCs determined?

Cell counts and viability are determined using a Nexcelom Cellometer® with acridine orange and propidium iodide to identify live and dead nucleated cells, respectively, per the recommendations provided by Nexcelom. Given the cellular debris that can be present, we do not recommend the use of trypan blue-based cell counting methods, as this will overestimate the number of dead cells.