A compound attribute that is the ratio of amount of activin receptor type-1-like (human) in blood to amount of ephrin-A4 (human) in blood. The trait is OBA_2055776 (ACVRL1/EFNA4 protein level ratio in blood). Also known as: the ratio of amount of activin receptor type-1-like (human) in blood to amount of ephrin-A4 (human) in blood.