A compound attribute that is the ratio of amount of mediator of RNA polymerase II transcription subunit 18 (human) in blood to amount of SH2B adapter protein 3 (human) in blood. The trait is Ontology of Biological Attributes identifier OBA_2053793 (MED18/SH2B3 protein level ratio in blood). Also known as: the ratio of amount of mediator of RNA polymerase II transcription subunit 18 (human) in blood to amount of SH2B adapter protein 3 (human) in blood.