[BNP or NT-proBNP: "that is the question"]

Area of Science:

• Cardiology
• Clinical Chemistry
• Biomarker Analysis

Background:

• B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) are crucial biomarkers for diagnosing dyspnea in emergency settings.
• Variability in these natriuretic peptides can complicate accurate diagnosis and patient management.

Purpose of the Study:

• To compare the diagnostic utility of BNP and NT-proBNP in a cohort of 119 dyspneic patients.
• To investigate factors influencing the accuracy and reliability of BNP and NT-proBNP measurements.

Main Methods:

• Comparative analysis of BNP and NT-proBNP blood levels in 119 emergency department patients presenting with dyspnea.
• Correlation of biomarker results with final clinical diagnoses.
• Assessment of pre-analytical factors (e.g., sample handling time, collection tubes) and patient-specific factors (e.g., renal function) on biomarker levels.

Main Results:

• Of 119 patients, 57 had coherent BNP and NT-proBNP results confirming clinical diagnosis.
• Nine congestive heart failure patients showed unexpectedly low levels, with six experiencing significant sample-to-lab delays.
• Forty-three patients had discordant results; BNP instability in vitro, exacerbated by glass EDTA tubes and transport delays, was noted.
• Ten patients showed elevated NT-proBNP or false positives, with five having renal dysfunction indicated by high creatinine.

Conclusions:

• BNP and NT-proBNP measurements are valuable for dyspnea diagnosis but are susceptible to pre-analytical variables and patient renal status.
• Sample handling protocols, including minimizing delays and appropriate collection tubes, are critical for maintaining biomarker integrity.
• Diagnostic cut-offs for natriuretic peptides should be adjusted based on a patient's degree of renal impairment to improve diagnostic accuracy.