A compound attribute that is the ratio of amount of scavenger receptor class F member 2 (human) in blood to amount of tumor necrosis factor receptor superfamily member 21 (human) in blood. The trait is OBA_2055740 (SCARF2/TNFRSF21 protein level ratio in blood). Also known as: the ratio of amount of scavenger receptor class F member 2 (human) in blood to amount of tumor necrosis factor receptor superfamily member 21 (human) in blood.