A compound attribute that is the ratio of amount of low affinity immunoglobulin epsilon Fc receptor (human) in blood to amount of tumor necrosis factor receptor superfamily member 9 (human) in blood. The trait is FCER2/TNFRSF9 protein level ratio in blood (Ontology of Biological Attributes entry OBA_2055213). Also known as: the ratio of amount of low affinity immunoglobulin epsilon Fc receptor (human) in blood to amount of tumor necrosis factor receptor superfamily member 9 (human) in blood.