A compound attribute that is the ratio of amount of protein delta homolog 1 (human) in blood to amount of prolyl endopeptidase FAP (human) in blood. The trait is DLK1/FAP protein level ratio in blood (OBA_2053625). Also known as: the ratio of amount of protein delta homolog 1 (human) in blood to amount of prolyl endopeptidase FAP (human) in blood.