In heart failure evaluation, which statement best describes BNP and NT-proBNP?

• A. NT-proBNP has a shorter half-life than BNP.
• B. BNP is more affected by renal function than NT-proBNP.
• C. NT-proBNP has a longer half-life and is more affected by renal function; age increases baseline levels.
• D. Age decreases baseline natriuretic peptide levels.

Answer: (C)

In heart failure assessment, it’s important to recognize how BNP and NT-proBNP differ in behavior in the circulation. BNP is the active hormone with a relatively short half-life, so its levels respond quickly but don’t stay elevated as long. NT-proBNP is an inert fragment that has a longer half-life, so it remains detectable in the blood for a longer period after release. Clearance is also different: NT-proBNP is cleared mainly by the kidneys, so renal function has a stronger influence on its concentration. Additionally, baseline natriuretic peptide levels tend to rise with age, even in the absence of heart failure.

Thus, the description that NT-proBNP has a longer half-life and is more affected by renal function, with age leading to higher baseline levels, best reflects these pharmacokinetic and physiological realities.