title: Multicentre evaluation of a new point-of-care test for the determination of NT-proBNP in whole blood.
abstract: BACKGROUND
  The Roche CARDIAC proBNP point-of-care (POC) test is the first test intended for the quantitative determination of N-terminal pro-brain natriuretic peptide (NT-proBNP) in whole blood as an aid in the diagnosis of suspected congestive heart failure, in the monitoring of patients with compensated left-ventricular dysfunction and in the risk stratification of patients with acute coronary syndromes.
  
  
  METHODS
  A multicentre evaluation was carried out to assess the analytical performance of the POC NT-proBNP test at seven different sites.
  
  
  RESULTS
  The majority of all coefficients of variation (CVs) obtained for within-series imprecision using native blood samples was below 10% for both 52 samples measured ten times and for 674 samples measured in duplicate. Using quality control material, the majority of CV values for day-to-day imprecision were below 14% for the low control level and below 13% for the high control level. In method comparisons for four lots of the POC NT-proBNP test with the laboratory reference method (Elecsys proBNP), the slope ranged from 0.93 to 1.10 and the intercept ranged from 1.8 to 6.9. The bias found between venous and arterial blood with the POC NT-proBNP method was < or =5%. All four lots of the POC NT-proBNP test investigated showed excellent agreement, with mean differences of between -5% and +4%. No significant interference was observed with lipaemic blood (triglyceride concentrations up to 6.3 mmol/L), icteric blood (bilirubin concentrations up to 582 micromol/L), haemolytic blood (haemoglobin concentrations up to 62 mg/L), biotin (up to 10 mg/L), rheumatoid factor (up to 42 IU/mL), or with 50 out of 52 standard or cardiological drugs in therapeutic concentrations. With bisoprolol and BNP, somewhat higher bias in the low NT-proBNP concentration range (<175 ng/L) was found. Haematocrit values between 28% and 58% had no influence on the test result. Interference may be caused by human anti-mouse antibodies (HAMA) types 1 and 2. No significant influence on the results with POC NT-proBNP was found using volumes of 140-165 muL. High NT-proBNP concentrations above the measuring range of the POC NT-proBNP test did not lead to false low results due to a potential high-dose hook effect.
  
  
  CONCLUSIONS
  The POC NT-proBNP test showed good analytical performance and excellent agreement with the laboratory method. The POC NT-proBNP assay is therefore suitable in the POC setting.
authors.affiliation: Abteilung für Kardiologie, Angiologie und Pulmonologie, Universitätsklinikum Heidelberg, Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Zugck
authors.forename: Manfred
authors.initials: M
authors.lastname: Nelles
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.forename: Paul O
authors.initials: PO
authors.lastname: Collinson
authors.forename: David C
authors.initials: DC
authors.lastname: Gaze
authors.forename: Bert
authors.initials: B
authors.lastname: Dikkeschei
authors.forename: Eberhard
authors.initials: E
authors.lastname: Gurr
authors.forename: Wiebke
authors.initials: W
authors.lastname: Hayen
authors.forename: Markus
authors.initials: M
authors.lastname: Haass
authors.forename: Christoph
authors.initials: C
authors.lastname: Hechler
authors.forename: Viviane
authors.initials: V
authors.lastname: van Hoof
authors.forename: Khadija
authors.initials: K
authors.lastname: Guerti
authors.forename: Carl
authors.initials: C
authors.lastname: van Waes
authors.forename: Gert
authors.initials: G
authors.lastname: Printzen
authors.forename: Kai
authors.initials: K
authors.lastname: Klopprogge
authors.forename: Ilse
authors.initials: I
authors.lastname: Schulz
authors.forename: Rainer
authors.initials: R
authors.lastname: Zerback
mesh_terms: D002138:Calibration; D006331:Heart Diseases / Q000097:blood*; D006333:Heart Failure / Q000097:blood; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D019095:Point-of-Care Systems / Q000592:standards*; D011933:Reagent Kits, Diagnostic / Q000592:standards; D012016:Reference Values; D015203:Reproducibility of Results; D018401:Sample Size; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D010446:Peptide Fragments; D011933:Reagent Kits, Diagnostic; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain