A compound attribute that is the ratio of amount of cystatin-C (human) in blood to amount of interleukin-18-binding protein (human) in blood. The trait is CST3/IL18BP protein level ratio in blood (OBA_2054476, an Ontology of Biological Attributes entry). Also known as: the ratio of amount of cystatin-C (human) in blood to amount of interleukin-18-binding protein (human) in blood.