SMAD1/ZBTB16 protein level ratio in blood (OBA_2055655) can be described as follows. A compound attribute that is the ratio of amount of mothers against decapentaplegic homolog 1 (human) in blood to amount of zinc finger and BTB domain-containing protein 16 (human) in blood. Also known as: the ratio of amount of mothers against decapentaplegic homolog 1 (human) in blood to amount of zinc finger and BTB domain-containing protein 16 (human) in blood.