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Brain natriuretic peptide is stable in whole blood and can be measured using a simple rapid assay: implications for clinical practice
  1. David R Murdocha,b,
  2. John Byrneb,
  3. James J Mortona,
  4. Theresa A McDonagha,b,
  5. Stephen D Robba,
  6. Suzanne Clementsa,
  7. Ian Fordc,
  8. John J V McMurraya,b,
  9. Henry J Dargiea,b
  1. aMedical Research Council’s Clinical Research Initiative in Heart Failure, University of Glasgow, Glasgow, UK, bDepartment of Cardiology, Western Infirmary, Glasgow, UK, cRobertson Centre for Biostatistics, University of Glasgow, Glasgow, UK
  1. Dr Murdoch, MRC Clinical Research Initiative in Heart Failure, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK.


Objectives To compare the stability of brain natriuretic peptide (BNP) to that of N-terminal atrial natriuretic peptide (NT-ANP) in whole blood and plasma stored under different conditions. To compare a rapid, simple, direct (unextracted) BNP assay to a conventional assay using plasma extraction.

Design Blinded, prospective, comparative study.

Setting Tertiary referral cardiology department.

Subjects Forty two subjects (24 men, 18 women) comprising 28 patients with left ventricular systolic dysfunction (LVSD) ranging from mild to severe and 14 healthy volunteers.

Main outcome measures Stability of NT-ANP and BNP when stored as whole blood or plasma at room temperature over three days. Reproducibility of measurements.

Results—BNP was stable in whole blood stored at room temperature for three days; mean change in concentration −7.4% (95% CI 0.6 to −14.8), (direct), −6.3% (5.0 to −16.4), (extracted); whereas a significant decline in BNP concentration was noted in plasma stored at room temperature; −23.2% (−13.7 to −31.6), (direct); −14.4% (−3.2 to −24.3), (extracted). By contrast a small non-significant rise in NT-ANP concentration was noted both in whole blood and plasma stored at room temperature for three days; whole blood +8.6% (+22.3 to −3.5), plasma +6.3%, (23.2 to −8.4). The reproducibility of the BNP measurements, and particularly the rapid, direct, measurement, was superior to that for NT-ANP.

Conclusions BNP is shown to be stable in whole blood for three days and can be measured using a rapid, simple assay. Routine assay of BNP is feasible in ordinary clinical practice and may be of value to general practitioners and hospital based physicians in the diagnosis and management of patients with LVSD. Samples can be sent to a central laboratory without special handling requirements.

  • brain natriuretic peptide
  • atrial natriuretic peptide
  • heart failure
  • diagnosis

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