In the subsequent validation study by Williams et al. [25], it is possible that the NT-proBNP cut point of 395 pg/ml was partly due to at least 20% of controls having ILD, which is in line with the findings from our study that suggest a higher NT-proBNP cut point (≥ 360.5 pg/ml) is required to separate PAH from ILD groups. The gene discussed is NPPB; the disease is interstitial lung disease.