COMP and hemarthrosis: In 2015 van Vulpen et al. have experimentally induced hemarthrosis in dogs to evaluate the change of urinary CTX-II and serum COMP, CS846 and C1, 2C in response to a joint bleed, the study has demonstrated a significant increase in urinary CTX-II from day two to seven (from 75% to 155%) and serum COMP from baseline to day two (+46%).