The Scottish Bowel Screening Programme is an enormous potential research resource; half a million people in Scotland do their bowel screening test each year. If we could obtain meaningful data on the gut microbiota in these individuals, many clinical questions could be answered using nested case-control studies relating gut microbiota profiles to cancer, obesity, cardiovascular and metabolic diseases and Alzheimer's disease. As individuals are screened from age 50 to 74 years, there would also be excellent opportunities for longer-term longitudinal studies.

Since 2017, the bowel screening programme has used qFIT testing for faecal haemoglobin. Patients collect a tiny (2 miligram) sample of their faeces into 2 mililiter of buffer but only approximately 6 microliter is required for testing. The goal of this study is to investigate whether the large number of patients' samples available from the National Bowel Screening Programme could be used in future gut microbiome studies using the leftover faeces in buffer in the qFIT tests.

We aim to test the hypothesis that the 2 mg of faeces suspended in buffer reagent in the qFIT cassette will be sufficient to perform 16S rRNA gene sequencing and will yield comparable results to conventionally collected faecal samples, thus allowing us to study the large number of patients' samples available from the National Bowel Screening Programme in future studies.

If we could demonstrate that the DNA from these faeces yields similar results to that from conventionally collected specimens (e.g. 15-20 ml of faeces collected into a 30 ml stool sample pot), this could allow us to study the large number of patients' samples available from the National Bowel Screening Programme in future studies.

Other studies have investigated the potential for using fresh or frozen residual FIT test buffer instead of intact stool samples to measure faecal microbial features by 16S rRNA gene sequencing, using OC-Auto FIT cartridges (Polymedco Inc) which add 10 mg of faeces to 2 ml of buffer, but buffer stability is lower than for the EXTEL collection picker cartridges (7 days vs 32 days at room temperature; 28 days vs 120 days at 2-8oC).

We hypothesise that the small amount of faeces suspended in buffer reagent in the qFIT cassette will be sufficient to perform 16S rRNA gene sequencing and will yield comparable results to conventionally collected faecal samples.

We shall:

1. determine whether 500 ul of buffer/faeces mix from qFIT collection cassettes will yield sufficient DNA for 16S rRNA gene sequencing or whether 1.5 to 2 ml is required
2. compare 16S rRNA gene sequencing of fresh faeces from 16 human volunteers (processed within 24 hours) using qFIT cassettes and conventional faecal collection methods
3. determine the suitability of faeces collected by qFIT, held in the cassette for durations commensurate with samples handled in the Scottish Bowel Screening Programme, up to 14 days
4. quantify the DNA present in 100 qFIT samples surplus to requirements from symptomatic patients from Aberdeen Royal Infirmary, to determine the proportion of samples with adequate DNA for 16S rRNA gene sequencing.

Inclusion Criteria:

• Healthy men and women
• Aged 18 to 65
• BMI 18.5 and 30 kg/m2

Exclusion Criteria:

• A member of Prof Kiltie's lab
• Cconsumed antibiotics within the last 3 months
• Pregnant or breastfeeding
• Cannot drop your samples off at the Rowett Institute
• Have any of the following: History of cardiovascular disease/stroke, diabetes, gastrointestinal disease, autoimmune disorders or cancer.

Healthy people between 18 and 65 years old.