The present invention relates to Glycoprotein VI (GPVI) fusion proteins (GPVI-fusion proteins) comprising a tag like myc, GST, HA, FLAG, STREP but preferably a Immunoglobulin molecule (Ig), more preferably a Fc portion of said Ig and a protein or oligopeptide having the biological activity of GPVI (GPVI-like protein) which is binding to collagen and their use in methods and kits for the screening of potential agonists or antagonists for GPVI-colagen and/or platelet-collagen interaction is disclosed. Further, pharmaaceutical compositions and therapeutic methods are provided comprising such GPVI-fusion proteins for the treatment of thrombotic and cardiovascular events and disorders related to GPVI-collagen and/or platelet-collagen interactions.