Home cryopreservation of fecal samples:an effective strategy for longitudinal studies using multi-omics approaches

To the Editor:Accumulating evidence has shown that gut microbiota–host interactions play vital roles in human health and disease.However,the dynamic equilibria between microbes and their hosts limit the utility of single strains or microbial signatures as markers for disease risk prediction and outcome assessment.[1]Analysis of changes in the gut microenvironment using multi-omics approaches has now become routine.[2]In inflammatory bowel disease,and especially during the acute phase,a significant shift in the gut microenvironment occurs within 2 weeks.Therefore,effective strategies to obtain fecal samples every 2 to 3 days are needed.However,challenges in specimen storage,transport,and handling limit long-term sampling ability.The microbial composition of fecal samples stored at room temperature for>24 h is significantly altered.Storage of fecal specimens at−80°C immediately after evacuation is standard procedure but is impractical in real-life situations.An alternative is a storage at−20°C for up to 1 month followed by sample transport and laboratory analysis.The objective of this study was to evaluate whether the gut microenvironment in fecal specimens collected every 2 to 3 days and stored at home at−20°C for up to 1 month could be preserved.