From the Guidelines
An elevated B-type Natriuretic Peptide (BNP) level is strongly indicative of heart failure, particularly when the clinical presentation is consistent with this diagnosis.
Interpretation of BNP Levels
- BNP < 100 ng/L: Heart failure is unlikely 1
- BNP 100-500 ng/L: Grey zone, clinical correlation and further testing are necessary 1
- BNP > 500 ng/L: Heart failure is likely 1 It is essential to consider the clinical context and pretest probability when interpreting BNP levels, as elevated levels can also be seen in other conditions such as pulmonary embolism, sepsis, and renal failure 1.
Clinical Correlation
BNP levels should be correlated with clinical and imaging assessment to confirm a diagnosis of heart failure and exclude non-cardiac causes of elevated BNP levels 1.
Prognostic Value
Elevated BNP levels are also strong predictors of mortality and re-admission in patients with heart failure, with higher levels indicating a worse prognosis 1. In patients with chronic heart failure, BNP levels can be used to monitor disease severity and prognosis, but the utility of BNP levels may be limited by their non-specificity and potential lag behind acute changes in hemodynamic measurements 1.
From the Research
Interpretation of Elevated B-type Natriuretic Peptide (BNP) Levels
Elevated BNP levels can be indicative of various cardiac and non-cardiac conditions. The interpretation of BNP levels is influenced by several factors, including:
- Age, gender, and body mass index (BMI) 2
- Presence of comorbidities, such as renal failure, pulmonary hypertension, and chronic obstructive pulmonary disease 2, 3
- Clinical settings, including acute coronary syndromes, diastolic dysfunction, atrial fibrillation, and valvular heart disease 2, 4
Clinical Implications of Elevated BNP Levels
Elevated BNP levels can be associated with:
- Congestive heart failure (CHF), with levels greater than 400 pg/mL indicating significant CHF 4
- Poor prognosis, with higher mortality and more hospital readmissions 4
- Non-cardiac diseases, such as pulmonary embolism, cor pulmonale, and renal failure 2, 3, 5
- Critical illness, including acute decompensated CHF and sepsis 2
Diagnostic Value of BNP Levels
BNP levels can be used to:
- Rule out CHF in dyspneic patients, with levels less than 100 pg/mL indicating a low likelihood of CHF 4
- Diagnose CHF, with levels greater than 400 pg/mL indicating significant CHF 4
- Guide therapy and discharge planning for patients admitted with decompensated heart failure 4
- Assist in the diagnosis and management of combined heart and renal failure 3