GP1BA/SELP protein level ratio in blood (OBA_2053416, an Ontology of Biological Attributes id) can be described as follows. A compound attribute that is the ratio of amount of platelet glycoprotein Ib alpha chain (human) in blood to amount of P-selectin (human) in blood. Also known as: the ratio of amount of platelet glycoprotein Ib alpha chain (human) in blood to amount of P-selectin (human) in blood.