A compound attribute that is the ratio of amount of ephrin-A4 (human) in blood to amount of lysosome membrane protein 2 (human) in blood. The trait is EFNA4/SCARB2 protein level ratio in blood (OBA_2055597, an Ontology of Biological Attributes identifier). Also known as: the ratio of amount of ephrin-A4 (human) in blood to amount of lysosome membrane protein 2 (human) in blood.