A compound attribute that is the ratio of amount of carbonic anhydrase 13 (human) in blood to amount of vacuolar protein sorting-associated protein VTA1 homolog (human) in blood. The trait is CA13/VTA1 protein level ratio in blood (Ontology of Biological Attributes entry OBA_2055728). Also known as: the ratio of amount of carbonic anhydrase 13 (human) in blood to amount of vacuolar protein sorting-associated protein VTA1 homolog (human) in blood.