Biological variation of secretoneurin; a novel cardiovascular biomarker implicated in arrhythmogenesis.

Background: Secretoneurin is a novel prognostic biomarker that may predict mortality in heart failure and the occurrence of ventricular arrhythmias. This study reports the within subject variation (CV), between subject variation (CV), reference change values (RCV) and index of individuality (II) of secretoneurin.

Methods: Thirty healthy volunteers were included. Non-fasting samples were obtained between 8 and 10 am once a week for ten weeks. Secretoneurin was analyzed in duplicate using ELISA. No outliers were present according to Burnett and Reeds' criteria. Simple linear regression did not identify significant trends. Variance homogeneity in the analytical variance and CV were tested using Cochrane's and Bartlett's tests and four participants were excluded. Calculation of CV, CV and RCV were done on ln transformed data as described by Fokkema, the II was calculated using retransformed data.

Results: The median age of the participants was 36 years and 53% were female. Non-fasting glucose, eGFR, cTnT and NT-proBNP concentrations were within the normal range. Median secretoneurin concentrations were 38 pmol/L (women) and 33 pmol/L (men), p-value < 0.001. CV and CV were 9.8% (CI 8.7% to 11.0%) and 20.0 (CI 15.4% to 28.0%), respectively. RCV were 38.7% (CI 35.5% to 42.7%) and -27.9 (CI -29.9 to -26.2) and the II were 0.60 (CI 0.42-0.78). No gender differences were present.

Conclusion: Secretoneurin has a fairly low CV, CV, RCV and II, indicating that it could be suitable as a diagnostic or prognostic biomarker and that delta values in serial samplings may be preferable for identifying clinical changes.