Histology interval (reference standard) | ||||||
---|---|---|---|---|---|---|

High risk: 1 year | Intermediate risk: 3 years | Low risk: 5 years | Low risk: no surveillance | No adenoma: no surveillance | Total | |

NBI colonoscopy interval | ||||||

High risk: 1 year | (a) 9 | 4 | 0 | (b′) 3 | (b) 2 | 18 |

Intermediate risk: 3 years | 3 | 30 | 12 | 10 | 2 | 57 |

Low risk: 5 years | 2 | 13 | 46 | 52 | 13 | 126 |

Low risk: no surveillance | (c′) 0 | 4 | 9 | (d′) 100 | 19 | 132 |

No adenoma: no surveillance | (c) 0 | 4 | 27 | 28 | (d) 107 | 166 |

Total | 14 | 55 | 94 | 193 | 143 | (N) 499 |

*Adenoma**present (solid line partitions)*Test sensitivity=sum of cells in box (a)/sum of cells in boxes (a)+(c)=297/356=83.4%.

Test specificity=sum of cells in box (d)/sum of cells in boxes (d)+(b)=107/143=74.8%.

Error rate=(b+c)/N=95/499=19.0%.

*Surveillance required (dashed line partitions)*Test sensitivity=sum of cells in box (a)/sum of cells in boxes (a)+(c′)=119/163=73.0%.

Test specificity=sum of cells in box (d′)/sum of cells in boxes (d′)+(b′)=254/336=75.6%.

Exact matching=sum of cells with matching surveillance interval / N=339/499=67.9%.

Conservative matching=sum of cells with matching or over surveillance/N=437/499=87.6%.

Error rate=(b′+c′)/N=126/499=25.2%.

NBI, narrow band imaging.