A compound attribute that is the ratio of amount of complement C1q tumor necrosis factor-related protein 1 (human) in blood to amount of collagen alpha-1(XVIII) chain (human) in blood. The trait is Ontology of Biological Attributes id OBA_2053175 (C1QTNF1/COL18A1 protein level ratio in blood). Also known as: the ratio of amount of complement C1q tumor necrosis factor-related protein 1 (human) in blood to amount of collagen alpha-1(XVIII) chain (human) in blood.