Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the faecal immunochemical test (FIT) at thresholds of 40 µg/g and 10 µg/g for colorectal cancer in participants who completed one, two, or three tests and underwent colonic examination
| FIT threshold (µg/g) | Test | Completed test* | Participants with colorectal cancer | Participants without colorectal cancer | Sensitivity (95% CI) | Specificity (95% CI) | PPV (95% CI) | NPV (95% CI) | |||
| n | TP | FN | FP | TN | % | % | % | % | |||
| 40 | First | 5225 | 8 | 21 | 309 | 4887 | 27.6 (12.7 to 47.2) | 94.1 (93.4 to 94.7) | 2.5 (1.1 to 4.9) | 99.6 (99.3 to 99.7) | |
| Second† | 4864 | 7 | 9 | 218 | 4630 | 43.8 (19.8 to 70.1) | 95.5 (94.9 to 96.1) | 3.1 (1.3 to 6.3) | 99.8 (99.6 to 99.9) | ||
| Third‡ | 4448 | 2 | 5 | 178 | 4263 | 28.6 (3.7 to 71.0) | 96.0 (95.4 to 96.5) | 1.1 (0.1 to 4.0) | 99.9 (99.7 to 100.0) | ||
| Over two tests | CTA§ | 5181 | 15 | 9 | 527 | 4630 | 62.5 (40.6 to 81.2) | 89.8 (88.9 to 90.6) | 2.8 (1.6 to 4.5) | 99.8 (99.6 to 99.9) | |
| PA¶ | 5225 | 15 | 14 | 527 | 4669 | 51.7 (32.5 to 70.6) | 89.9 (89.0 to 90.7) | 2.8 (1.6 to 4.5) | 99.7 (99.5 to 99.8) | ||
| Over three tests | CTA** | 4990 | 17 | 5 | 705 | 4263 | 77.3 (54.6 to 92.2) | 85.8 (84.8 to 86.8) | 2.4 (1.4 to 3.7) | 99.9 (99.7 to 100.0) | |
| PA†† | 5225 | 17 | 12 | 705 | 4491 | 58.6 (38.9 to 76.5) | 86.4 (85.5 to 87.4) | 2.4 (1.4 to 3.7) | 99.7 (99.5 to 99.9) | ||
| 10 | First | 5225 | 15 | 14 | 718 | 4478 | 51.7 (32.5 to 70.6) | 86.2 (85.2 to 87.1) | 2.0 (1.1 to 3.4) | 99.7 (99.5 to 99.8) | |
| Second† | 4458 | 5 | 6 | 437 | 4010 | 45.5 (16.7 to 76.6) | 90.2 (89.3 to 91.0) | 1.1 (0.4 to 2.6) | 99.9 (99.7 to 99.9) | ||
| Third‡ | 3853 | 1 | 3 | 345 | 3504 | 25.0 (0.6 to 80.6) | 91.0 (90.1 to 91.9) | 0.3 (0.0 to 1.6) | 99.9 (99.8 to 100.0) | ||
| Over two tests | CTA§ | 5191 | 20 | 6 | 1155 | 4010 | 76.9 (56.4 to 91.0) | 77.6 (76.5 to 78.8) | 1.7 (1.0 to 2.6) | 99.9 (99.7 to 99.9) | |
| PA¶ | 5225 | 20 | 9 | 1155 | 4041 | 69.0 (49.2 to 84.7) | 77.8 (76.6 to 78.9) | 1.7 (1.0 to 2.6) | 99.8 (99.6 to 99.9) | ||
| Over three tests | CTA** | 5028 | 21 | 3 | 1500 | 3504 | 87.5 (67.6 to 97.3) | 70.0 (68.7 to 71.3) | 1.4 (0.9 to 2.1) | 99.9 (99.8 to 100.0) | |
| PA†† | 5225 | 21 | 8 | 1500 | 3696 | 72.4 (52.8 to 87.3) | 71.1 (69.9 to 72.4) | 1.4 (0.9 to 2.1) | 99.8 (99.6 to 99.9) | ||
*Participants who tested positive at a given threshold at year 1 or 2 were excluded from subsequent analyses.
†Includes participants who completed their second FIT, either at year 2 or 3.
‡Includes participants who completed their third FIT.
§Includes participants who completed at least two FITs or who tested positive at year 1. Participants were classed as positive if they tested positive with either of their first two FITs.
¶Includes participants who completed at least one FIT. Participants were classed as positive if they tested positive with either of their first two FITs.
**Includes participants who completed all three FITs or who tested positive with any FIT. Participants were classed as positive if they tested positive with any FIT.
††Includes participants who completed at least one FIT. Participants were classed as positive if they tested positive with any FIT.
CTA, cumulative test analysis; FN, false negative; FP, false positive; PA, programme analysis; TN, true negative; TP, true positive.