We applied in vitro transcribed poliovirus RNA diluted into HeLa cell total RNA to the Virochip as an additional positive control to quantify Virochip sensitivity. Using the E-predict analysis tool, the lowest detectable concentration of poliovirus was 1 viral RNA per 10 5 HeLa RNA molecules (approximately 10 polio gRNAs per cell equivalent of HeLa RNA; Figure S1 ). The raw reads were first separated by barcode and analyzed as individual data sets as described in the Methods. The bioinformatic filtering process consisted of removing low complexity and low quality sequences, then filtering sequences of human origin ( Figure 1 ). After the filtering steps, an average of 1.9% of the initial reads remained, with an absolute average of 60,000 reads remaining per sample ( Figure 1 and Table 1 ). A few of the barcode datasets appeared to have a larger non-human fraction. Upon further inspection, the non-human components were accounted for by known library preparation contaminants, such as E. coli and S. cerevisiae.