CRTAM/TNFRSF9 protein level ratio in blood (Ontology of Biological Attributes term OBA_2054512) can be described as follows. A compound attribute that is the ratio of amount of cytotoxic and regulatory T-cell molecule (human) in blood to amount of tumor necrosis factor receptor superfamily member 9 (human) in blood. Also known as: the ratio of amount of cytotoxic and regulatory T-cell molecule (human) in blood to amount of tumor necrosis factor receptor superfamily member 9 (human) in blood.