A compound attribute that is the ratio of amount of plexin-A4 (human) in blood to amount of sushi domain-containing protein 1 (human) in blood. The trait is PLXNA4/SUSD1 protein level ratio in blood (Ontology of Biological Attributes identifier OBA_2053525). Also known as: the ratio of amount of plexin-A4 (human) in blood to amount of sushi domain-containing protein 1 (human) in blood.