While two studies measured BNP levels early in the clinical presentation, and these showed a good discriminatory ability [18, 19], other studies allowed BNP to be tested up to 3 hours (IQR 0.5–14) [10] or 48 hours after presentation and these were less able to distinguish ARDS/ALI from CPE [21]. The gene discussed is NPPB; the disease is acute respiratory distress syndrome.