Participant characteristics
| Characteristic | Strata | OGD | Colonoscopy | CT colonography | Total |
| Number of participants | – | 15 (3 transnasal endoscopy) | 10 | 10 | 35 |
| Sex | Male | 8 (53.3%) | 5 (50.0%) | 6 (60.0%) | 19 (54.3%) |
| Female | 7 (46.7%) | 5 (50.0%) | 4 (40.0%) | 16 (45.7%) | |
| Age | <50 years | 5 (33.3%) | 0 (0.0%) | 1 (10.0%) | 6 (17.1%) |
| 50–59 years | 4 (26.7%) | 5 (50.0%) | 1 (10.0%) | 10 (28.6%) | |
| 60–69 years | 2 (13.3%) | 2 (20.0%) | 3 (30.0%) | 7 (20.0%) | |
| 70+ years | 4 (26.7%) | 3 (30.0%) | 5 (50.0%) | 12 (34.3%) | |
| Previous test experience | None | 4 (26.7%) | 3 (30.0%) | 4 (40.0%) | 11 (31.4%) |
| Same test previously | 10 (66.7%) | 4 (40.0%) | 1 (10.0%) | 15 (42.9%) | |
| Different test previously | 1 (6.7%) | 3 (30.0%) | 5 (50.0%) | 9 (25.7%) |
OGD, oesophagogastroduodenoscopy.