Table 1.
Summary of findings (sensitivity, specificity, predictive values) for diagnostic tests for colorectal cancer detection evaluated by at least four primary diagnostic studies
| Index test | Sensitivity | Specificity | PPV | 1-NPV |
| Age (> 50) | 91% | 36% | 10% | 2% |
| Sex (male) | 62% | 55% | 13% | 3% |
| Family history | 16% | 91% | 6% | 4% |
| Weight loss | 20% | 89% | 9% | 6% |
| Abdominal pain | 35% | 59% | 5% | 7% |
| Rectal bleeding | 44% | 66% | 7% | 4% |
| All bleeding, dark blood | 35% | 85% | 14% | 5% |
| All bleeding, mixed with stool | 51% | 71% | 6% | 3% |
| Change in bowel habits | 52% | 61% | 9% | 4% |
| Diarrhoea present | 20% | 73% | 6% | 10% |
| Constipation | 13% | 72% | 6% | 9% |
| Two week rule positive | 92% | 42% | 14% | 3% |
| Iron deficiency anaemia | 13% | 92% | 13% | 8% |
| Faecal occult blood test positive | ||||
| Chemical | 75% | 86% | 28% | 1% |
| Immunological | 95% | 84% | 21% | 0% |
The results are expressed as medians or pooled estimates. Adapted from Jellema et al[24]. PPV: Positive predictive value; NPV: Negative predictive value.