A compound attribute that is the ratio of amount of marginal zone B- and B1-cell-specific protein (human) in blood to amount of tumor necrosis factor receptor superfamily member 13B (human) in blood. The trait is Ontology of Biological Attributes entry OBA_2054647 (MZB1/TNFRSF13B protein level ratio in blood). Also known as: the ratio of amount of marginal zone B- and B1-cell-specific protein (human) in blood to amount of tumor necrosis factor receptor superfamily member 13B (human) in blood.