A compound attribute that is the ratio of amount of complement receptor type 2 (human) in blood to amount of tumor necrosis factor receptor superfamily member 13B (human) in blood. The trait is CR2/TNFRSF13B protein level ratio in blood (OBA_2054604, an Ontology of Biological Attributes entry). Also known as: the ratio of amount of complement receptor type 2 (human) in blood to amount of tumor necrosis factor receptor superfamily member 13B (human) in blood.