FIG. 4.

Bar chart showing the ratios of leukocytes to MCF7 cells for different nominal spiking ratios. Blood from three separate donors was measured and experiments were performed in triplicate. For control experiments (which followed an identical protocol, without MCF7) 0 events were seen within the MCF7 gate in five cases, 1 event in 3 cases and 3 events in 1 case. Around 100 MCF7 cells were measured in the 1:1000 dilution samples. The nominal ratio is based on a nominal leukocyte count of 6 cells/nL. Actual measured samples had higher leukocyte counts thus increasing the measured leukocyte to MCF7 ratios.