Estimated test positivity cut-offs that must be applied to 1-sample and 2-sample tests to return an equivalent sensitivity for advanced neoplasia, together with respective population positivity rates (colonoscopy workloads)
| Sensitivity for advanced neoplasia | Cut-off achieving sensitivity equivalence (n=626, µg Hb/g faeces) | Population test-positivity rate* (n=32 413) | ||
| 1-sample | 2-sample† | 1-sample | 2-sample† | |
| 55% | 4.0 | 16.4 | 16.35% to 5298 15.9%–16.8% | 8.18% to 2652 7.9%–8.5% |
| 50% | 6.0 | 22.4 | 11.74% to 3806 11.4%–12.1% | 6.45% to 2091 6.2%–6.7% |
| 45% | 9.2 | 25.6 | 8.5% to 2755 8.2%–8.8% | 5.83% to 1889 5.6%–6.1% |
| 40% | 12.6 | 28.4 | 6.57% to 2130 6.3%–6.8% | 5.39% to 1748 5.1%–5.6% |
| 35% | 18.4 | 32.2 | 4.73% to 1532 4.5%–5.0% | 4.86% to 1575 4.6%–5.1% |
| 30% | 24.2 | 38.8 | 3.82% to 1239 3.6%–4.0% | 4.18% to 1354 4.0%–4.44% |
| 25% | 29.8 | 48.0 | 3.22% to 1045 3.0%–3.4% | 3.46% to 1120 3.3%–3.7% |
| 20% | 37.6 | 68.6 | 2.63% to 852 2.5%–2.8% | 2.57% to 832 2.4%–2.7% |
| 15% | 49.2 | 97.2 | 2.02% to 656 1.9%–2.2% | 1.97% to 639 1.8%–2.1% |
| 10% | 83.8 | 157.2 | 1.30% to 422 1.2%–1.4% | 1.30% to 422 1.2%–1.4% |
*Positivity rate, n and 95% CI
†Maximum value of the two samples.
Hb, haemoglobin.