Development of blood-based biomarker tests for early detection of colorectal neoplasia: Influence of blood collection timing and handling procedures.

•The impact of bowel preparation solutions on blood-based, cancer-associated biomarkers have been poorly investigated.•125 subjects scheduled for a colonoscopy investigating potential colorectal cancer contributed with two blood samples. The collection was before and after usage of bowel preparation solution.•The study demonstrated a systematic, statistical significant difference between pre- and post bowel preparation in three independent biomarkers (BAG4, CyFra21-1 and cell-free DNA).