From the Guidelines
False elevation of N-terminal pro b-type natriuretic peptide (NT pro BNP) levels can occur due to various factors, including renal impairment 1, which has been shown to increase NT-proBNP concentrations. Additionally, obesity 1 has an inverse relationship with BNP and NT-proBNP concentrations, and age and gender can also influence NT-proBNP values 1. Other factors that can cause false elevation of NT pro BNP levels include:
- Chronic kidney disease 1, which can lead to increased NT-proBNP concentrations
- Pulmonary embolism and severe pulmonary hypertension 1, which can cause right ventricular dysfunction and increase NT-proBNP levels
- Atrial fibrillation and sepsis 1, which can reduce the accuracy of NT-proBNP for detecting heart failure
- Valvular heart disease and left ventricular hypertrophy 1, which can increase NT-proBNP concentrations
- Endocrine disorders such as hyperaldosteronism, Cushing's syndrome, and hyperthyroidism 1, which can affect NT-proBNP levels. It is essential to consider these factors when interpreting NT-proBNP results to avoid misdiagnosis or misinterpretation of heart failure.
From the Research
Causes of False Elevation of NT pro BNP
- Analytical interference: A study reported a false positive BNP result possibly caused by a macro-BNP, which was only immunoreactive in the Abbott Architect BNP immunoassay 2.
- Chronic kidney disease (CKD): Elevated NT-proBNP levels are common in patients with CKD, and the correlation between NT-proBNP and renal function is strong (r = -0.525; P < 0.001) 3.
- Left ventricular dysfunction: NT-proBNP levels are significantly higher in patients with left ventricular dysfunction (LVD) compared to those without LVD 4.
- Volume overload: Persistent post-dialytic volume overload correlates with elevated NT-proBNP levels in patients with LVD 4.
- Other factors: Age, diabetes, prior coronary artery disease events, and myocardial injury also increase the prevalence of elevated NT-proBNP levels 5.
Factors Affecting NT pro BNP Levels
- Renal function: Decreased renal function affects NT-proBNP levels, with a strong correlation between eGFR and NT-proBNP (r = -0.525; P < 0.001) 3.
- Cardiac disease: NT-proBNP levels predict underlying heart disease, including coronary artery disease and left ventricular hypertrophy, in asymptomatic CKD patients 6, 5.
- Assay interference: Different immunoassays may yield varying results, highlighting the importance of analytical interference in NT-proBNP measurements 2.