Final answer:
NT-Pro BNP blood level is related to heart failure, not kidney function, thyroid disorders, or liver function. This hormone helps reduce blood pressure and decreases Na+ levels by promoting sodium and water excretion.
Step-by-step explanation:
NT-Pro BNP blood level is associated with heart failure. B-type or ventricular natriuretic peptide is released from the ventricles in response to increased blood pressure and blood volume, leading to a decrease in systemic vascular resistance and central venous pressure, thus reducing blood pressure. Additionally, BNP leads to decreased Na+ levels because it promotes the excretion of sodium and water, mainly by its action on the kidneys, where it inhibits sodium reabsorption and suppresses the secretion of renin and aldosterone. This mechanism of action helps to differentiate heart failure from other conditions such as kidney or liver function disorders and thyroid disorders, which are not directly linked to BNP levels.