Ontology of Biological Attributes term OBA_2055747 (SDC4/SMAD1 protein level ratio in blood) can be described as follows. A compound attribute that is the ratio of amount of syndecan-4 (human) in blood to amount of mothers against decapentaplegic homolog 1 (human) in blood. Also known as: the ratio of amount of syndecan-4 (human) in blood to amount of mothers against decapentaplegic homolog 1 (human) in blood.