A newer assay measuring NT-terminal proBNP (NT-proBNP) is more sensitive to detect heart failure and used in many institutions. The levels of BNP and NT-proBNP are essentially the same in normal individuals, but in the presence of heart failure the NT-proBNP is approximately four times higher than the corresponding BNP level, thus reducing the likelihood of a result in the ambiguous range (i.e. BNP level of 300 which is high, but not quite definite heart failure which would be > 400).

NT-proBNP levels are also higher in patients with atrial fibrillation and acute coronary syndrome. The level of NT-proBNP may be helpful not only to evaluate heart failure, but also to detect acute coronary syndromes in patients with chest pain presenting to the emergency department where it has been found to be elevated (although further investigation is underway).