Colvera for Detection of Disease Recurrence

This is an observational, prospective comparison study, where blood is collected for assay of methylated BCAT1 and IKZF1 DNA and CEA, from subjects who have undergone curative treatment for primary CRC of stages II and III (AJCC) and who are in remission and scheduled for follow-up radiological imaging as part of their surveillance program for recurrence. Participation is for one visit only as part of each subject's surveillance-monitoring schedule. Two K2-EDTA blood tubes and two PAXgene™ tubes will be collected Any evidence of methylated BCAT1 and/or IKZF1 DNA in blood represents a Colvera "positive" result. CEA levels of 5ug/L or higher will represent a "positive" result. Sensitivity and specificity of the Colvera and CEA test will be estimated and compared in a paired fashion in each case where recurrence status has been investigated and determined by the site clinical management team. Blood testing shall be performed and analyzed by qualified staff blinded to clinical status. This is a cross-sectional observational non-significant risk study, and test results will not be used for clinical management, i.e. there will be no interventions in subjects consenting to participate in this Research Study.