From the Guidelines
The BNP cutoff for indicating heart failure is generally 100 ng/L, as defined by the National Institute for Health and Clinical Excellence guideline 1. This cutoff is used to define normal serum natriuretic peptide levels, with raised levels being between 100 ng/L and 400 ng/L, and high levels being above 400 ng/L. However, it's essential to consider the clinical context and other factors that can affect BNP levels, such as age, renal dysfunction, obesity, and acute coronary syndromes. For example, age-related cutoffs for NT-proBNP have been proposed, with values of 450 pg/mL for <50 years, 900 pg/mL for 50 to 75 years, and 1800 pg/mL for >75 years 1. Additionally, BNP and NT-proBNP levels can be elevated in non-HF disease states, requiring cautious interpretation in the presence of comorbidities such as cardiac, pulmonary, and renal disease. Some key points to consider when interpreting BNP levels include:
- Age and sex influence BNP levels, but their overall impact is less significant compared to comorbidities
- Underlying factors such as cardiac, pulmonary, and renal disease can increase natriuretic peptides above current thresholds for HF
- Elevations of BNP and NT-proBNP in the setting of pulmonary hypertension and pulmonary embolism are related to right ventricular dysfunction and have significant prognostic value independently of underlying LV dysfunction
- The accuracy of natriuretic peptides for the detection of HF is reduced in the setting of atrial fibrillation and sepsis, and careful interpretation is warranted. Overall, BNP and NT-proBNP are useful biomarkers for diagnosing heart failure, but their interpretation requires careful consideration of the clinical context and potential confounding factors.
From the Research
BNP Cutoff for Indicating Heart Failure
The B-type natriuretic peptide (BNP) cutoff for indicating heart failure can vary depending on the study and population.
- A study published in the American Heart Journal in 2006 found that a BNP level < 100 pg/mL was found in only 10% of patients with heart failure at hospital discharge 2.
- Another study published in Congestive Heart Failure in 2007 found that BNP levels can be elevated in heart failure, but extremely high levels (> 4000 pg/mL) are more likely to be determined by renal dysfunction than by the severity of heart failure 3.
- A study published in the International Journal of Cardiology in 2016 found that extremely elevated BNP levels (> 1694 pg/mL) were associated with older age, lower body mass index, and higher blood urea nitrogen and creatinine levels, as well as lower cardiac output and cardiac index 4.
- A study published in the International Journal of Cardiology in 2010 found that a discharge BNP cutoff of 250 pg/mL was predictive of a worse outcome in patients with heart failure 5.
- A study published in the Journal of International Medical Research in 2015 found that a BNP level > 1000 pg/mL was associated with worse 3-year survival and was often found in patients with heart failure, as well as those with community-acquired pneumonia 6.
Key Findings
- BNP levels can be used to indicate heart failure, but the cutoff value can vary depending on the population and study.
- Extremely high BNP levels (> 4000 pg/mL) may be more likely to be determined by renal dysfunction than by the severity of heart failure.
- A discharge BNP cutoff of 250 pg/mL may be predictive of a worse outcome in patients with heart failure.
- A BNP level > 1000 pg/mL is associated with worse 3-year survival and is often found in patients with heart failure or community-acquired pneumonia.