NPPB and interstitial lung disease: If any of the following screening tests are positive, the experts suggest that the patient must be referred for RHC: a) the DETECT algorithm; b) the 2015 ESC/ERS recommendations for TTE; and c) FVC/DLCO ratio >1.6 (assuming none-to-mild interstitial lung disease) and >2-fold upper limit of normal of NT-proBNP.