In 2021 and 2022, researchers carried out an implementation trial that considered how the capsule sponge test might be used to screen for Barrett's oesophagus using a mobile clinic in East Anglia. This paper offers insights from 15 months of ethnographic fieldwork studying the trial. It aims to highlight the value of the test in offering reassurance to worried patients, particularly to those with a family history of oesophageal adenocarcinoma. It also considers the variety of aims people held for the capsule sponge test, including the hope that it would address their symptoms of acid reflux, and the conflict that sometimes emerged as a result. The second half of the paper uses fieldwork carried out in virtual support groups for people with Barrett's oesophagus to explore experiences postdiagnosis, which sometimes were defined by fear of future cancers. It describes notable differences between the care offered to people with morphological risk conditions like Barrett's oesophagus and the care given to those with genetic risk conditions, including the provision of genetic counselling. More broadly, the paper highlights a tension between patient-centred and risk-centred medicine that is likely to grow as healthcare services continue to shift towards preventative approaches.