Assessment of ISET^® intra-assay accuracy and precision.

<p>50 A549 cells were spiked into 5 mL of blood (n = 3 experiments, 43 to 49 cells per 5 mL). The number of tumor cells found on each spot after ISET^® filtration (each corresponding to the filtration of 1 mL of blood) was recorded. Experiments were done on 5 spots but for intra-assay precision and accuracy only the assessment of the number of cells found on single spots or randomly grouped spots (any 1, any 2, any 3, any 4 spots) is relevant. The cell counting on the combination of all the 5 spots was used as reference. Results show that cell counting on four spots exhibited a representative mean tumor cells value per mL of blood. (A) Bar chart with the mean tumor cell number per spot and corresponding standard error of the mean (error bars) depending on the number of spots analyzed. Error bars are calculated using the standard deviation in different combinations of any 4 spots, any 3 spots, any 2 spots or any 1 spot, respectively. If only one spot is considered, standard deviation is higher than when counting 4 spots, showing that counting on four spots gives a reliable mean tumor cells' value per mL of blood. (B) Table indicating the number of tumor cells found on each spot for each of the five experiments, the 95% confidence interval (CI), the precision (%CV) and the accuracy (%error) depending on the number of spots analyzed (1 to 4) as compared to the analysis on five spots.