FLT4/KDR protein level ratio in blood (OBA_2055261, an Ontology of Biological Attributes entry) can be described as follows. A compound attribute that is the ratio of amount of vascular endothelial growth factor receptor 3 (human) in blood to amount of vascular endothelial growth factor receptor 2 (human) in blood. Also known as: the ratio of amount of vascular endothelial growth factor receptor 3 (human) in blood to amount of vascular endothelial growth factor receptor 2 (human) in blood.