title: Measuring B-Type Natriuretic Peptide From Capillary Blood or Venous Sample: Is It the Same?
abstract: BACKGROUND
  In recent years, several systems have been implemented to achieve quick and non-invasive measurements of B-type natriuretic peptide (BNP). Among them, AlereTMHeart 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Cardiology Unit, Presidio Sanitario Intermedio "Elena d'Aosta", ASL Napoli 1 Centro, Napoli, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: De Vecchis
authors.affiliation: Cardiology Unit, Presidio Sanitario Intermedio "Elena d'Aosta", ASL Napoli 1 Centro, Napoli, Italy.
authors.forename: Carmelina
authors.initials: C
authors.lastname: Ariano
keywords: B-type natriuretic peptide; Capillary blood; Heart failure; Immunoassay; Point-of-care; Venous blood