A compound attribute that is the ratio of amount of receptor tyrosine-protein kinase erbB-4 (human) in blood to amount of tissue factor (human) in blood. The trait is ERBB4/F3 protein level ratio in blood (Ontology of Biological Attributes id OBA_2054734). Also known as: the ratio of amount of receptor tyrosine-protein kinase erbB-4 (human) in blood to amount of tissue factor (human) in blood.