Measuring B-Type Natriuretic Peptide From Capillary Blood or Venous Sample: Is It the Same?

BACKGROUND: In recent years, several systems have been implemented to achieve quick and non-invasive measurements of B-type natriuretic peptide (BNP). Among them, Alere(TM) Heart Check (AHC) BNP test represents the most recent advancement. It is a rapid point-of-care (POC) immunoassay, projected for measuring BNP directly from a capillary whole blood sample. This study aimed at comparing the analytical and clinical performances of this new POC to our reference method (Abbott Architect System). METHODS: One hundred eleven patients with stable chronic heart failure (CHF) referring to one cardiac rehabilitation center were enrolled from December 2013 to May 2015. These patients were subjected to a simultaneous capillary (AHC) and plasma (Abbott) BNP measurements. Clinical and analytical performances of AHC were assessed and compared to the reference method. RESULTS: Capillary BNP showed a good correlation with the reference method (r = 0.94, P < 0.0001), although the values diverged when BNP was higher than 1,500 pg/mL. Indeed, the AHC had a relatively poor precision and the coefficient of variability was 10.1% and 18% for low and high controls, respectively. However, both methods showed similar diagnostic performances in discriminating the patients with heart failure in New York Heart Association (NYHA) class I from those belonging to NYHA classes II-III, with values of area under the curve (AUC) of 0.983 and 0.984, respectively, and equivalent sensitivity, specificity, and positive and negative likelihood ratios. CONCLUSION: The AHC BNP test is a good POC able to provide reliable information about the hemodynamic status of CHF patients, especially of those belonging to NYHA classes I-III.