Table 1. United Kingdom screening parameter model inputs.
| Screening patterns | Value | Reference |
|---|---|---|
| Start and stop age (years) | 20–65 | Department of Health Bulletin (2004) |
| Screening coverage | ||
| % Screened every 3 years (dependent on age) | 33–73 | Department of Health Bulletin (2004) |
| % Never screened in lifetime | 7 | |
| Test characteristics | ||
| Cytology – sensitivity (specificity) | 0.41–0.67 (0.966) | |
| Probability of accurate biopsy CIN diagnosis | 0.536 | Cuzick et al (1995); Hopman et al (1998); Mitchell et al (1998) |
| Probability of biopsy underdiagnosed CIN lesion | 0.2 | |
| Probability of biopsy overdiagnosed CIN lesion | 0.263 | |
| Colposcopy – sensitivity (specificity) | 0.96 (0.48) | |
| Screening practices | ||
| Borderline dyskaryosis to triage cytology, (colposcopy) (%) | 80 (20) | |
| Mild dyskaryosis to triage cytology, (colposcopy) (%) | 58 (42) | Department of Health Bulletin (2004) |
| ⩾Moderate dyskaryosis to colposcopy (%) | 100 | |
| Negative triage cytology to regular screening (repeat test) (%) | 84 (16) | Assumption/(NHS, 2004) |
| Positive triage cytology to colposcopy (%) | 100 | |
| Negative colposcopy/biopsy to regular screening (%) | 50 | |
| Negative colposcopy/biopsy to increased screening (%) | 50 | |
| CIN 1 diagnosis to increased screening, (treatment) (%) | 50 (50) | |
| CIN 2 or 3 diagnoses to treatment (%) | 100 | |
CIN = cervical intraepithelial neoplasia; Cytology sensitivity = probability of abnormal cytology given true state is CIN 1+. The model includes probability of abnormal cytology according to lesion type (i.e., CIN 1 to CIN 3) and therefore a range of values is provided; cytology specificity = probability of normal cytology given true state is negative for lesions.