Using faecal immunochemical test (FIT) undertaken in a national screening programme for large-scale gut microbiota analysis

We read with great interest the article by Gudra et al 1 reporting a faecal immunochemical test (FIT; OC-Sensor, Eiken Chemical) commonly used in colonic neoplasia screening as a reliable sampling device for microbiome profiling when compared with immediately frozen samples from whole stool. The potential to use the FIT routinely completed by approximately 3 million participants annually as part of the English Bowel Cancer Screening Programme2 to understand the role of gut microbiome in colorectal neoplasia holds great promise, not least because of the convenience to individuals, cost-savings associated with use of routinely collected samples, and methodological advantages of samples collected before microbiome-altering procedures (eg, bowel cleansing).3 We aimed to validate and expand on the finding of Gudra et al 1 by investigating performance of the Bowel Cancer Screening Programme (BCSP) FIT, analysing more subjects, testing longer-term storage, investigating different methods of concentration and comparing with OMNIgene.GUT (OG; DNA Genotek), a widely used research device for stool DNA preservation at ambient temperature.4 We considered bacterial profile stability over time, mimicking real-world research scenarios with storage of FIT samples for up to 20 days prior to DNA extraction. We …