What is a normal Pro-B-type Natriuretic Peptide (Pro-BNP) level?

From the Guidelines

Normal Pro-B-type Natriuretic Peptide (Pro-BNP) levels are defined as BNP levels <100 ng/L or NT-proBNP levels <400 ng/L. When evaluating Pro-BNP levels, it's essential to consider the patient's age, sex, and laboratory reference ranges, as these factors can influence the normal values of BNP 1. According to the National Institute for Health and Clinical Excellence guideline, normal serum natriuretic peptide levels are defined as BNP levels <100 ng/L or NT-proBNP levels <400 ng/L 1.

Key Considerations

• BNP and NT-proBNP tests are valuable diagnostic tools for assessing heart failure, with higher values correlating with more severe disease 1.
• Factors like renal dysfunction, obesity, and certain medications can affect these levels, so interpretation should consider the patient's complete clinical picture 1.
• Regular monitoring of these biomarkers can help track heart failure progression and treatment effectiveness.
• The normal age-adjusted ranges of BNP and NT-proBNP vary, with suggested ranges including:
  • Young adults: BNP < 25 pg/mL, NT-proBNP < 70 pg/mL
  • 45-59 years: BNP < 100 pg/mL (males), NT-proBNP < 164 pg/mL (females)

  • 60 years: BNP < 98 pg/mL (males), NT-proBNP < 225 pg/mL (females) 1

Clinical Implications

• Elevated Pro-BNP levels suggest heart failure or other cardiac conditions causing ventricular strain 1.
• Prompt diagnosis and treatment can improve outcomes, including morbidity, mortality, and quality of life 1.
• BNP levels <100 ng/L or NT-proBNP levels <400 ng/L are generally considered normal, but it's crucial to interpret these values in the context of the patient's overall clinical picture 1.

From the Research

Normal Pro-B-type Natriuretic Peptide (Pro-BNP) Levels

• The normal levels of Pro-BNP can vary based on age and sex, with females generally having higher levels than males 2.
• According to a study, NT-proBNP levels increase with age, and a cut-off level of 125 pg/ml can be useful to exclude cardiac dysfunction in symptomatic individuals or to risk-stratify elderly individuals 2.
• Another study found that in males, the median NT-proBNP concentration at age <30 years was 21 pg/mL, rising to 38 pg/mL at 50 to 59 years, and 281 pg/mL at ≥80 years, while in females, the median NT-proBNP at age <30 years was 51 pg/mL, 66 pg/mL at 50 to 59 years, and 240 pg/mL at ≥80 years 3.
• The European Society of Cardiology (ESC) guidelines define an NT-Pro-BNP level above 125 pg/ml as indicating a high possibility of heart failure, and a level below 125 pg/ml as excluding the high possibility of heart failure 4.

Factors Influencing Pro-BNP Levels

• Age and sex are significant factors influencing Pro-BNP levels, with older age and female sex associated with higher levels 3, 2.
• Renal function may also influence circulating natriuretic peptide levels, including Pro-BNP 2.
• Other factors such as smoking, diabetes, and body mass index may also affect Pro-BNP levels, although the relationships between these factors and Pro-BNP levels are complex and may vary depending on the population being studied 3, 5, 4.

Clinical Significance of Pro-BNP Levels

• Pro-BNP levels are a useful marker for the evaluation of morbidity and mortality in heart failure patients, including those with diabetes 6, 4.
• Elevated Pro-BNP levels are associated with an increased risk of cardiovascular events and mortality, and can be used to risk-stratify patients with heart failure 6.
• However, Pro-BNP levels should be interpreted with caution, as they can be influenced by a range of factors and may not always accurately reflect cardiac function or prognosis 6.