Table 3.
Diagnostic performance in double-faecal immunochemical test cohort comparing first analysed test of patients who complete at least one test and investigation with greatest result in those who completed double-test protocol
| n | FIT (µg Hb/g) |
Sensitivity (%) |
Specificity (%) |
PPV (%) |
NPV (%) |
NNI | Pathology missed (%) |
Reduction in missed pathology (%) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| < 10 | ≥ 10 | < 10 | ≥ 10 | |||||||||
| CRC | FIT1 | 135 | 9 | 126 | 93.3 (87.7, 96.9) | 78.0 (76.6, 79.4) | 14.8 (12.5, 17.4) | 99.7 (99.3, 99.8) | 286 | 7 | 6.7 | |
| 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 | 49.3 | |
| AA | FIT1 | 136 | 62 | 74 | 54.4 (45.6, 63.0) | 76.4 (45.7, 63.0) | 8.7 (6.9, 10.8) | 97.6 (96.9, 98.2) | 42 | 11 | 45.6 | |
| 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 | 29.8 | |
| ACRN | FIT1 | 271 | 71 | 200 | 73.8 (68.1, 78.9) | 79.4 (78.0, 80.8) | 23.6 (20.7, 26.6) | 97.2 (96.5, 97.8) | 36 | 4 | 26.2 | |
| 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 | 29.8 | |
| IBD | FIT1 | 55 | 5 | 50 | 90.9 (80.0, 97.0) | 76.3 (74.8, 77.7) | 5.9 (4.4, 7.7) | 99.8 (99.5, 99.9) | 515 | 17 | 9.1 | |
| 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 | 0.0 | |
| SBP | FIT1 | 326 | 76 | 250 | 76.7 (71.7, 81.1) | 80.7 (79.2, 82.1) | 29.4 (26.4, 32.6) | 97.1 (96.3, 97.7) | 34 | 3 | 23.3 | |
| 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 | 27.0 | |
Values in parentheses are 95% confidence intervals. FIT, faecal immunochemical test; Hb, haemoglobin; PPV, positive predictive value; NPV, negative predictive value; NNI, number needed to investigate; CRC, colorectal cancer; FIT1, first (or only) FIT result; FITMAX, greatest of the two FIT results; AA, advanced adenoma; ACRN, advanced colorectal neoplasia; IBD, inflammatory bowel disease; SBP, significant bowel pathology.