Background: In our metabolomics studies we have noticed that repeated NMR acquisition on the same sample can result in altered metabolite signal intensities.
Aims: To investigate the reproducibility of repeated NMR acquisition on selected metabolites in serum and plasma from two large human metabolomics studies.
Methods: Two peak regions for each metabolite were integrated and changes occurring after reacquisition were correlated.
Results: Integral changes were generally small, but serum citrate signals decreased significantly in some samples.
Conclusions: Several metabolite integrals were not reproducible in some of the repeated spectra. Following established protocols, randomising analysis order and biomarker validation are important.
Keywords: Metabolomics; NMR; Plasma; Reproducibility; Serum.