A compound attribute that is the ratio of amount of cystatin-C (human) in blood to amount of insulin-like growth factor-binding protein 6 (human) in blood. The trait is CST3/IGFBP6 protein level ratio in blood (Ontology of Biological Attributes entry OBA_2054475). Also known as: the ratio of amount of cystatin-C (human) in blood to amount of insulin-like growth factor-binding protein 6 (human) in blood.