A compound attribute that is the ratio of amount of carbonic anhydrase 13 (human) in blood to amount of thymidine phosphorylase (human) in blood. The trait is Ontology of Biological Attributes term OBA_2055726 (CA13/TYMP protein level ratio in blood). Also known as: the ratio of amount of carbonic anhydrase 13 (human) in blood to amount of thymidine phosphorylase (human) in blood.