Characteristics of the three optimal cut-off points for predicted probability of GI cancer, as applied to the training and validation datasets
| Threshold | Criterion | Training dataset (%) | Validation dataset (%) | |
| Optimal cut-off 1 (1.5%) | NPV=100% | Sensitivity (95% CI) | 100.0 (97.7 to 100.0) | 100.0 (91.8 to 100.0) |
| NPV (95% CI) | 100.0 (98.0 to 100.0) | 100.0 (95.1 to 100.0) | ||
| Optimal cut-off 2 (7.4%) | G mean | Sensitivity (95% CI) | 75.8 (68.3 to 82.3) | 79.1 (63.9 to 89.9) |
| Specificity (95% CI) | 63.2 (60.9 to 65.5) | 67.7 (63.3 to 71.9) | ||
| Optimal cut-off 3 (11.1%) | PPV in highest quartile | Sensitivity (95% CI) | 56.1 (47.9 to 63.9) | 60.5 (44.4 to 75.0) |
| PPV (95% CI) | 18.6 (15.2 to 22.4) | 23.9 (16.2 to 32.9) | ||
GI, gastrointestinal; G mean, geometric mean; NPV, negative predictive value; PPV, positive predictive value.