Figure 1
From: Method validation of circulating tumour cell enumeration at low cell counts
Determination of analytical accuracy in CTC enumeration utilising BETI and QC samples. Certified QC samples containing SK-BR3 human tumour cells spiked at high and low numbers were assayed by a pool of analysts over a 3 month period in order to construct tolerance intervals (±) at β = 95%, 80% and 67%. Combined tolerance intervals for all analysts (a) versus tolerance intervals for a single analyst: (b), (c) and (d).