A compound attribute that is the ratio of amount of glutathione S-transferase A1 (human) in blood to amount of keratin, type I cytoskeletal 18 (human) in blood. The trait is Ontology of Biological Attributes term OBA_2053451 (GSTA1/KRT18 protein level ratio in blood). Also known as: the ratio of amount of glutathione S-transferase A1 (human) in blood to amount of keratin, type I cytoskeletal 18 (human) in blood.