A compound attribute that is the ratio of amount of proteinase-activated receptor 1 (human) in blood to amount of Kunitz-type protease inhibitor 2 (human) in blood. The trait is Ontology of Biological Attributes id OBA_2055334 (F2R/SPINT2 protein level ratio in blood). Also known as: the ratio of amount of proteinase-activated receptor 1 (human) in blood to amount of Kunitz-type protease inhibitor 2 (human) in blood.