Background: Clinical trial samples may be stored frozen for prolonged periods before analysis, which can reduce the immunoreactivity of numerous analytes, particularly peptides. We sought to determine the effect of 6 years of frozen storage on serum N-terminal pro-B-type natriuretic peptide (NT-proBNP).
Methods: NT-proBNP was measured from serum samples taken from 99 different patients enrolled in the CanPREDDICT study after <1 year of storage at -70 °C using the Roche first-generation NT-proBNP assay on an e411 instrument.