A compound attribute that is the ratio of amount of natural killer cells antigen CD94 (human) in blood to amount of T-lymphocyte surface antigen Ly-9 (human) in blood. The trait is KLRD1/LY9 protein level ratio in blood (OBA_2055540). Also known as: the ratio of amount of natural killer cells antigen CD94 (human) in blood to amount of T-lymphocyte surface antigen Ly-9 (human) in blood.