PTPRF/PTPRS protein level ratio in blood (Ontology of Biological Attributes identifier OBA_2053218) can be described as follows. A compound attribute that is the ratio of amount of receptor-type tyrosine-protein phosphatase F (human) in blood to amount of receptor-type tyrosine-protein phosphatase S (human) in blood. Also known as: the ratio of amount of receptor-type tyrosine-protein phosphatase F (human) in blood to amount of receptor-type tyrosine-protein phosphatase S (human) in blood.