FEN1/PADI4 protein level ratio in blood (OBA_2055308, an Ontology of Biological Attributes id) can be described as follows. A compound attribute that is the ratio of amount of flap endonuclease 1 (human) in blood to amount of protein-arginine deiminase type-4 (human) in blood. Also known as: the ratio of amount of flap endonuclease 1 (human) in blood to amount of protein-arginine deiminase type-4 (human) in blood.