A compound attribute that is the ratio of amount of ephrin-A1 (human) in blood to amount of phosphoinositide-3-kinase-interacting protein 1 (human) in blood. The trait is Ontology of Biological Attributes id OBA_2055592 (EFNA1/PIK3IP1 protein level ratio in blood). Also known as: the ratio of amount of ephrin-A1 (human) in blood to amount of phosphoinositide-3-kinase-interacting protein 1 (human) in blood.