SFTPA2/SFTPD protein level ratio in blood (OBA_2055641) can be described as follows. A compound attribute that is the ratio of amount of pulmonary surfactant-associated protein A2 (human) in blood to amount of pulmonary surfactant-associated protein D (human) in blood. Also known as: the ratio of amount of pulmonary surfactant-associated protein A2 (human) in blood to amount of pulmonary surfactant-associated protein D (human) in blood.