The effect of protease inhibition on the temporal stability of NT-proBNP in feline plasma at room temperature

David J Connolly, Melanie J Hezzell, Virginia Luis Fuentes, Yu-Mei Chang, Rebecca Swan, Harriet M Syme

Research output: Contribution to journalArticle (Academic Journal)peer-review

7 Citations (Scopus)


OBJECTIVES: To evaluate whether the addition of a protease inhibitor (PI) to feline plasma improves the temporal stability of N-terminal pro-B-type natriuretic peptide (NT-proBNP).

ANIMALS, MATERIALS AND METHODS: Forty-four EDTA blood samples were collected from 42 cats with cardiac disease or hyperthyroidism. Samples were separated within 15 min of collection and the plasma stored at -80 °C. Samples were thawed and each separated into 2 aliquots, one of which was mixed with PI. Each was subdivided into 5 aliquots, which remained at room temperature (RT) for zero, 24, 48, 96 or 120 h before being returned to storage at -80 °C. NT-proBNP was measured using a commercially-available ELISA.

RESULTS: There was no difference in NT-proBNP measurements between plain and PI samples at time zero (P = 0.836) or 24 h (P = 0.293). At subsequent time-points NT-proBNP was higher in the PI than the plain samples (P < 0.05). An overall effect of time at RT was detected for plain (P < 0.001) and PI samples (P < 0.001).

CONCLUSIONS: The addition of PI to feline plasma significantly reduces, but does not eliminate, degradation of NT-proBNP at RT. This degradation occurs over a time course comparable to postal transportation of samples for laboratory analysis and may alter the clinical interpretation of results.

Original languageEnglish
Pages (from-to)13-9
Number of pages7
JournalJournal of Veterinary Cardiology
Issue number1
Publication statusPublished - Mar 2011


  • Animals
  • Cats
  • Natriuretic Peptide, Brain
  • Peptide Fragments
  • Protease Inhibitors
  • Specimen Handling
  • Temperature
  • Time Factors


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