Study of the impact of storage conditions on the stability of metabolites in fecal samples for 1H NMR metabolomics analysis

Metabolomics is an emerging science with strong potential for clinical applications and personalized medicine. However, the use of stool samples collected at patients’ homes raises important logistical and pre-analytical challenges, particularly regarding metabolite stability. This study aimed to assess the impact of storage conditions and processing delays on faecal metabolite stability. Stool samples from ten healthy volunteers were stored in two matrices (phosphate-buffered saline alone or supplemented with sodium azide 0.02%), at different temperatures and for varying time periods before centrifugation. Nuclear magnetic resonance (NMR) analysis enabled the identification and quantification of 28 metabolites. While a few metabolites showed significant instability after two hours, the majority remained stable under both conditions. These findings highlight the importance of selecting appropriate matrices based on targeted metabolites and support the development of standardized, clinically applicable protocols for faecal metabolomics.