A compound attribute that is the ratio of amount of tumor necrosis factor receptor superfamily member 5 (human) in blood to amount of immunoglobulin superfamily member 8 (human) in blood. The trait is Ontology of Biological Attributes term OBA_2054204 (CD40/IGSF8 protein level ratio in blood). Also known as: the ratio of amount of tumor necrosis factor receptor superfamily member 5 (human) in blood to amount of immunoglobulin superfamily member 8 (human) in blood.