In general, heart failure is unlikely at BNP values <100 pg/ml and is very likely at BNP values >500 pg/ml and, similarly, unlikely at NT-proBNP values <300 pg/ml and very likely at NT-proBNP values >450 pg/ml (>900 pg/ml in patients above 50 years of age) (Kay JD et al. 2003). Here, NPPB is linked to heart failure.