NT-ProBNP clinical test significance and reference values

Reference range: 0-75 years old: 0~125, ≥76 years old: 0~450 ng/L.

Influencing factors:

The biological half-life of NT-proBNP is 1 to 2 hours, while that of BNP is only about 20 minutes, so its storage stability in vitro is poor (about 4 hours at room temperature or 4°C).

Clinical significance:

1. BNP and NT-proBNP are both clinically good markers for diagnosing heart failure (HF). BNP is synthesized in cardiomyocytes. First, the preprohormone (preproBNP containing 134 amino acids) is synthesized, and then the 24-amino acid signal peptide is removed in the cardiomyocytes to form the corresponding prohormone (proBNP), which is then combined through the membrane. It is cleaved by protease into an amino-terminal fragment containing 76 amino acids (NT-proBNP) and a carboxyl-terminal fragment (BNP) containing 32 amino acids, and both are secreted into the blood circulation in equal molar amounts.

2. BNP can increase the glomerular filtration rate and inhibit sodium reabsorption, thereby promoting natriuresis. BNP can also inhibit the activity of central and peripheral sympathetic nerves, inhibit the renin-angiotensin-aldosterone system, thereby relaxing vascular smooth muscles, dilating arteries and veins, and reducing blood pressure and ventricular preload.

3． The increase in BNP or NT-proBNP in heart failure is related to the degree of heart failure and has unique predictive value for left ventricular dysfunction or mortality from AMI. It can be used to estimate the condition of HF patients, monitor efficacy, judge prognosis or classify risk.