OBJECTIVETo determine the reference value of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) in subjects without heart diseases.

METHODSThe plasma concentration of NT-proBNP was measured with ELISA method in 300 adults excluded heart disease through various examinations including electrocardiography, echocardiography, X-ray and coronary artery angiography. The plasma NT-proBNP concentration was compared between age-groups 30-39, 40-49, 50-59, 60-69 and > or = 70 years old, between male and female in the same age-group and between subjects with and without hypertension, diabetes and obesity. A multiple linear regression analysis was used to detect factors influencing NT-proBNP among age, sex, body mass index, blood pressure, heart rate, serum creatinine, hypertension, diabetes mellitus, use of angiotensin-converting-enzyme inhibitors, Ca(2+)-antagonist, and beta-blocker.

RESULTSThe plasma NT-proBNP concentration increased in proportion to aging in male subjects more than 60 years old (P < 0.05), remained unchanged in males less than 60 years old and females (P > 0.05). Plasma NT-proBNP concentration was significantly higher in female (170-660 pmol/L) than in male (160-470 pmol/L) in subjects less than 60 years old (P < 0.05) and significantly lower in female (180-560 pmol/L) than in male (180-760 pmol/L) in subjects more than 60 years old (P < 0.05). Multiple linear regression analysis demonstrated that age was the only independent predictor for plasma NT-proBNP in these subjects (P < 0.01).

CONCLUSIONThe plasma concentration of NT-proBNP in subjects without heart diseases was different between male and female, and was increasing with age in male subjects more than 60 years old.