Impact of prolonged blood incubation and extended serum storage at room temperature on the human serum metabolome

Abstract

Metabolomics is a powerful technology with broad applications in life science that, like other-omics approaches, requires high-quality samples to achieve reliable results and ensurereproducibility. Therefore, along with quality assurance, methods to assess sample quality regardingpre-analytical confounders are urgently needed. In this study, we analyzed the response of thehuman serum metabolome to pre-analytical variations comprising prolonged blood incubation andextended serum storage at room temperature by using gas chromatography-mass spectrometry(GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) -based metabolomics.We found that the prolonged incubation of blood results in a statistically significant 20% increaseand 4% decrease of 225 tested serum metabolites. Extended serum storage affected 21% of theanalyzed metabolites (14% increased, 7% decreased). Amino acids and nucleobases showed thehighest percentage of changed metabolites in both confounding conditions, whereas lipids wereremarkably stable. Interestingly, the amounts of taurine and O-phosphoethanolamine, which haveboth been discussed as biomarkers for various diseases, were 1.8- and 2.9-fold increased after 6 hof blood incubation. Since we found that both are more stable in ethylenediaminetetraacetic acid(EDTA) blood, EDTA plasma should be the preferred metabolomics matrix.