A compound attribute that is the ratio of amount of cathepsin F (human) in blood to amount of sphingomyelin phosphodiesterase (human) in blood. The trait is CTSF/SMPD1 protein level ratio in blood (OBA_2054622). Also known as: the ratio of amount of cathepsin F (human) in blood to amount of sphingomyelin phosphodiesterase (human) in blood.