Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) may be a valuable biological marker in Colorectal Cancer (CRC). However, prospective validation of TIMP-1 as a biological marker should include a series of pre-analytical considerations. TIMP-1 is stored in platelets, which may degranulate during collection and storage. The aim of this study was to evaluate the influence of platelet TIMP-1 contamination on plasma TIMP-1 levels in healthy volunteers.