Assessing the Repeatability of NT-proBNP Testing Using Laboratory and Point of Care Testing in PAH

The purpose of this study is to examine N-terminal pro brain natriuretic peptide (NT-proBNP) and brain natriuretic peptide (BNP) biomarkers in a number of different settings including assessing the repeatability of laboratory and point of care testing (POCT), the effect of a time delay and exercise have on laboratory measurements. Also to compare the clinical and analytical performances of NT-proBNP and BNP POCT samples across the spectrum of disease severity and finally assess whether POCT in PAH can detect change in patients commencing or escalating PAH treatment.