Determination and stability of N-terminal pro-brain natriuretic peptide in saliva samples for monitoring heart failure

Sci Rep. 2021 Jun 22;11(1):13088. doi: 10.1038/s41598-021-92488-2.


Heart failure (HF) is the main cause of mortality worldwide, particularly in the elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) is the gold standard biomarker for HF diagnosis and therapy monitoring. It is determined in blood samples by the immunochemical methods generally adopted by most laboratories. Saliva analysis is a powerful tool for clinical applications, mainly due to its non-invasive and less risky sampling. This study describes a validated analytical procedure for NT-proBNP determination in saliva samples using a commercial Enzyme-Linked Immuno-Sorbent Assay. Linearity, matrix effect, sensitivity, recovery and assay-precision were evaluated. The analytical approach showed a linear behaviour of the signal throughout the concentrations tested, with a minimum detectable dose of 1 pg/mL, a satisfactory NT-proBNP recovery (95-110%), and acceptable precision (coefficient of variation ≤ 10%). Short-term (3 weeks) and long-term (5 months) stability of NT-proBNP in saliva samples under the storage conditions most frequently used in clinical laboratories (4, - 20, and - 80 °C) was also investigated and showed that the optimal storage conditions were at - 20 °C for up to 2.5 months. Finally, the method was tested for the determination of NT-proBNP in saliva samples collected from ten hospitalized acute HF patients. Preliminary results indicate a decrease in NT-proBNP in saliva from admission to discharge, thus suggesting that this procedure is an effective saliva-based point-of-care device for HF monitoring.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / analysis
  • Diagnostic Tests, Routine
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Healthy Volunteers
  • Heart Failure / diagnosis*
  • Heart Failure / metabolism
  • Heart Failure / physiopathology
  • Humans
  • Male
  • Middle Aged
  • Natriuretic Peptide, Brain / analysis*
  • Natriuretic Peptide, Brain / immunology*
  • Natriuretic Peptide, Brain / metabolism
  • Peptide Fragments / analysis*
  • Peptide Fragments / immunology*
  • Peptide Fragments / metabolism
  • Protein Stability
  • Saliva / chemistry
  • Specimen Handling / methods


  • Biomarkers
  • Peptide Fragments
  • pro-brain natriuretic peptide (1-76)
  • Natriuretic Peptide, Brain