MED18/SMAD1 protein level ratio in blood (OBA_2053794) can be described as follows. A compound attribute that is the ratio of amount of mediator of RNA polymerase II transcription subunit 18 (human) in blood to amount of mothers against decapentaplegic homolog 1 (human) in blood. Also known as: the ratio of amount of mediator of RNA polymerase II transcription subunit 18 (human) in blood to amount of mothers against decapentaplegic homolog 1 (human) in blood.