A compound attribute that is the ratio of amount of platelet-derived growth factor subunit A (human) in blood to amount of SPARC protein (human) in blood. The trait is Ontology of Biological Attributes term OBA_2054051 (PDGFA/SPARC protein level ratio in blood). Also known as: the ratio of amount of platelet-derived growth factor subunit A (human) in blood to amount of SPARC protein (human) in blood.