Table 4.
Diagnostic performance in those who completed the double-test protocol comparing the first faecal immunochemical test result with the greatest result of two tests
| n | FIT (µg Hb/g) |
Sensitivity (%) |
Specificity (%) | PPV (%) |
NPV (%) |
NNI | Pathology missed (%) |
Reduction in missed pathology (%) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| < 10 | ≥ 10 | < 10 | ≥ 10 | |||||||||
| CRC | FIT1 | 88 | 6 | 82 | 93.2 (85.7, 97.5) | 78.6 (77.0, 80.2) | 13.1 (10.5, 16.0) | 99.7 (99.4, 99.9) | 335 | 8 | 6.8 | |
| FITMAX | 88 | 3 | 85 | 96.6 (90.4, 99.3) | 71.2 (69.4, 73.0) | 10.4 (8.4, 12.7) | 99.8 (99.5, 99.9) | 606 | 10 | 3.4 | 50.0 | |
| AA | FIT1 | 97 | 42 | 55 | 56.7 (46.3, 66.7) | 77.5 (75.8, 79.1) | 8.8 (6.7, 11.3) | 97.9 (97.2, 98.5) | 48 | 11 | 43.3 | |
| FITMAX | 97 | 31 | 66 | 68.0 (57.8, 77.1) | 70.4 (68.5, 72.1) | 8.1 (6.3, 10.1) | 98.3 (97.6, 98.8) | 59 | 12 | 32.0 | 26.1 | |
| ACRN | FIT1 | 185 | 48 | 137 | 74.1 (67.1, 80.2) | 80.0 (78.4, 81.6) | 21.9 (18.7, 25.3) | 97.6 (96.8, 98.2) | 42 | 5 | 26.0 | |
| FITMAX | 185 | 34 | 151 | 81.6 (75.3, 86.9) | 72.8 (70.9, 74.5) | 18.4 (15.8, 21.3) | 98.1 (97.4, 98.7) | 53 | 5 | 18.4 | 29.2 | |
| IBD | FIT1 | 33 | 5 | 28 | 84.8 (68.1, 94.9) | 77.0 (75.4, 78.6) | 4.4 (3.0, 6.4) | 99.8 (99.4, 99.9) | 402 | 22 | 15.2 | |
| FITMAX | 33 | 3 | 30 | 90.9 (75.7, 98.1) | 69.7 (67.9, 71.5) | 3.7 (2.5, 5.2) | 99.8 (99.5, 99.9) | 606 | 27 | 9.1 | 40.1 | |
| SBP | FIT1 | 218 | 53 | 165 | 75.7 (69.4, 81.2) | 80.9 (79.3, 82.5) | 26.3 (22.9, 29.9) | 97.4 (96.6, 98.0) | 38 | 4 | 24.3 | |
| FITMAX | 218 | 37 | 181 | 83.0 (77.4, 87.8) | 73.6 (71.8, 75.4) | 22.1 (19.3, 25.1) | 98.0 (97.2, 98.6) | 49 | 5 | 17.0 | 30.0 | |
Values in parentheses are 95% confidence intervals. Hb, haemoglobin; FIT, faecal immunochemical test; PPV, positive predictive value; NPV, negative predictive value; NNI, number needed to investigate; CRC, colorectal cancer; FIT1, first FIT result; FITMAX, greatest of the two FIT results; AA, advanced adenoma; ACRN, advanced colorectal neoplasia; IBD, inflammatory bowel disease; SBP, significant bowel pathology.