Screening for Colon Cancer

The goal of this low-risk interventional study is to analyze participants' assessment of colorectal cancer screening program through screening method preference and experience after FOBT analysis in screaned participant population for colorectal cancer; could include any of the following: both sexes, age 50-69 years, asympthomatic volunteers. The main aims to answer are: * Values of experience of participants into screening programme. * Values of preferences of participants for screening methods. Participants will answer two questionnaires and they'll be given their information and clinical data to investigator or health personnel.

The objective of this low-risk interventional study is to evaluate whether the PreveCol® test has sufficient efficiency to be considered as a second-line method for the detection of both colorectal cancer and advanced adenomas when used prospectively in the screening population with a previous positive FOBT result, which could include any of the following: both sexes, age 50-69 years, asympthomatic volunteers. The main aims to be answered are: * Values of efficacy, efficiency, impact and safety of PreveCol. * Values of preferences of participants for screening methods. * Values of PREMs into screening programme. Participants will provide a blood sample prior to a screening colonoscopy, and complete two questionnaires. They will give their sample, information and clinical data to the investigator or health care personnel.