A compound attribute that is the ratio of amount of collagen alpha-3(VI) chain (human) in blood to amount of basement membrane-specific heparan sulfate proteoglycan core protein (human) in blood. The trait is OBA_2053874 (COL6A3/HSPG2 protein level ratio in blood). Also known as: the ratio of amount of collagen alpha-3(VI) chain (human) in blood to amount of basement membrane-specific heparan sulfate proteoglycan core protein (human) in blood.