SFTPD and acute respiratory distress syndrome: Certainty was moderate for SP-D discriminating severe disease, supported by AUCs of 0.741 (sensitivity 85.3% and specificity 44.6% at 145 ng/mL) in hospitalised CAP [18], 0.802 (76% and 70% at 180 ng/mL) in an ED CAP cohort [19], 0.699 for influenza-related ARDS [20] and 0.712 for hypoxaemic pneumonia in a low-resource setting [22].