All FIT brands: test results for combinations of three-sample FITs, haemoglobin values, and platelet counts in symptomatic patients in primary care related to diagnoses of CRC
| Test result | FIT and haemoglobin value, n= 13 863 | FIT, haemoglobin value, and platelet count, n= 10 973 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Positive FIT | Anaemiaa | Anaemiaa and positive FIT | Anaemiaa and/or positive FIT | Positive FIT | Thrombocytosisb | Thrombocytosisb and positive FIT | Thrombocytosisb and/or positive FIT | Thrombocytosisb and/or anaemiaa and/or positive FIT | |
| Colorectal cancer, n | 289 | 289 | 289 | 289 | 237 | 237 | 237 | 237 | 237 |
| True positive, n | 262 | 132 | 123 | 271 | 212 | 40 | 39 | 213 | 222 |
| False negative, n | 27 | 157 | 166 | 18 | 25 | 197 | 198 | 24 | 15 |
| False positive, n | 3858 | 3685 | 1356 | 6187 | 3135 | 875 | 355 | 3655 | 5394 |
| True negative, n | 9716 | 9889 | 12 218 | 7387 | 7601 | 9861 | 10 381 | 7081 | 5342 |
| Sensitivity, % | 90.7 | 45.7 | 42.6 | 93.8 | 89.5 | 16.9 | 16.5 | 89.9 | 93.7 |
| Specificity, % | 71.6 | 72.9 | 90.0 | 54.4 | 70.8 | 91.8 | 96.7 | 66.0 | 49.8 |
| PPV (95% CI) | 6.4. | 3.5 (2.9 to 4.1) | 8.3 (6.9 to 9.7) | 4.2 (3.7 to 4.7) | 6.3 (5.5 to 7.2) | 4.4 (3.0 to 5.7) | 9.9 (6.9 to 12.8) | 5.5 (4.8 to 6.2) | 4.0 (3.5 to 4.5) |
| NPV (95% CI) | 99.7 (99.6 to 99.8) | 98.4 (98.2 to 98.7) | 98.7 (98.5 to 98.9) | 99.8 (99.6 to 99.9) | 99.7 (99.5 to 99.8) | 98.0 (97.8 to 98.3) | 98.1 (97.9 to 98.4) | 99.7 (99.5 to 99.8) | 99.7 (99.6 to 99.9) |
| LR+ | 3.19 | 1.69 | 4.26 | 2.06 | 3.07 | 2.06 | 5.00 | 2.64 | 1.87 |
| LR– | 0.13 | 0.74 | 0.64 | 0.11 | 0.15 | 0.91 | 0.86 | 0.15 | 0.13 |
↵a Anaemia: haemoglobin value< 117 g/l in females, < 134 g/l in males.
↵b Thrombocytosis: > 387 × 109/l in females and > 348 × 109/l in males in Jämtland Härjedalen, Kronoberg, Västernorrland, Västerbotten; > 390 × 109/l in females and >350x109/l in males in Örebro. CI = confidence interval. CRC = colorectal cancer. FIT = faecal immunochemical test. LR− = negative likelihood ratio. LR+ = positive likelihood ratio. NPV = negative predictive value. PPV = positive predictive value.