(A) Input parameters: sensitivities for advanced adenomas at various cut-off levels according to the results of a diagnostic study that determined test performance characteristics of OC-Sensor Micro (Eiken Chemical, Tokyo, Japan).14 | |
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Cut-off level (ng haemoglobin/mL buffer)* | Sensitivity for advanced adenomas (%) |

≥11 | 50 |

≥14 | 47 |

≥22 | 45 |

≥36 | 38 |

≥45 | 36 |

≥50 | 35 |

(B) Based on these sensitivities, the number of subjects diagnosed with advanced adenomas at the various alternative scenarios was estimated in a two-step approach
| |

Step 1 |
Estimating the total number of subjects with advanced adenomas in the cohort at baseline:Given a sensitivity of 35% for advanced adenomas at a cut-off level of ≥50 ng/mL, those subjects diagnosed with advanced adenomas in the first FIT50 round (N=126) were considered to make up for 35% of all subjects with advanced adenomas in the cohort at baseline. Dividing N=126 by 35%, it can thus be estimated that 360 subjects in the cohort had advanced adenomas at baseline. |

Step 2 |
Estimating the number of subjects diagnosed with advanced adenomas in the hypothetical first round:This number (N=360) was multiplied with the sensitivity for advanced adenomas at the cut-off level of each respective scenario. For example, when using a cut-off level of 22 ng/mL in the first round, it was estimated that 162 subjects would have been diagnosed with advanced adenomas (N=360 multiplied by 45%). |

*To convert the cut-off levels into the unit ‘µg/g faeces’, the listed values need to be divided by 5 given that the test delivers 10 mg of faeces into 2 mL of buffer.

FIT, faecal immunochemical test for haemoglobin.