Cut-off values of AT(N) biomarkers based on different models
| Analysed samples | Aβ42 | p-tau181 | t-tau | NfL |
| Aβ PET− (n=47) vs Aβ PET+ (n=53) | ||||
| Area under the ROC curve (95% CI) | 0.940 (0.885 to 0.995) | 0.868 (0.794 to 0.941) | 0.898 (0.832 to 0.963) | 0.706 (0.591 to 0.821) |
| Cut-off value, pg/mL | 378.7 | 26.8 | 85.7 | 2428 |
| Sensitivity, % (95% CI) | 98.1 (90.1 to 99.9) | 83.0 (70.8 to 90.8) | 90.6 (79.8 to 95.9) | 89.1 (77.0 to 95.3) |
| Specificity, % (95% CI) | 85.1 (72.3 to 92.6) | 80.9 (67.5 to 89.6) | 80.9 (67.5 to 89.6) | 57.1 (42.2 to 70.9) |
| CU, Aβ PET− (n=31) vs ADD, Aβ PET+ (n=22) | ||||
| Area under the ROC curve | 0.962 (0.907 to 1.000) | 0.912 (0.834 to 0.990) | 0.963 (0.917 to 1.000) | 0.852 (0.735 to 0.969) |
| Cut-off value, pg/mL | 361.6 | 29.1 | 88.8 | 2650 |
| Sensitivity, % (95% CI) | 100 (85.1 to 100) | 95.5 (78.2 to 99.8) | 95.5 (78.2 to 99.8) | 85.0 (64.0 to 94.8) |
| Specificity, % (95% CI) | 87.1 (71.2 to 94.9) | 80.7 (63.7 to 90.8) | 90.3 (75.1 to 96.7) | 80.8 (62.1 to 91.5) |
| CU (n=53) vs ADD (n=56) | ||||
| Area under the ROC curve | 0.888 (0.821 to 0.954) | 0.805 (0.723 to 0.888) | 0.882 (0.818 to 0.947) | 0.831 (0.747 to 0.915) |
| Cut-off value, pg/mL | 288.6 | 29.0 | 91.0 | 3120 |
| Sensitivity, % (95% CI) | 82.1 (70.2 to 90.0) | 73.2 (60.4 to 83.0) | 76.8 (64.2 to 85.9) | 69.4 (55.5 to 80.5) |
| Specificity, % (95% CI) | 88.7 (77.4 to 94.7) | 79.3 (66.5 to 88.0) | 88.7 (77.4 to 94.7) | 89.1 (77.0 to 95.3) |
| Gaussian Mixture Model (n=194) | ||||
| Cut-off value, pg/mL | 359.6 | 30.6 | 105.3 | NA* |
The cutoffs were established at the highest Youden Index (sensitivity +specificity – 1) when comparing Aβ PET− with Aβ PET+, or comparing CU, Aβ PET− with ADD, Aβ PET+, or comparing CU with ADD. The sensitivity and specificity are for each cut-off value.
*Due to unimodal distribution.
ADD, Alzheimer’s disease dementia; Aβ, β-amyloid; CU, cognitively unimpaired subjects; NA, not available; NfL, neurofilament light chain; p-tau181, tau phosphorylated at threonine 181; ROC, receiver operating characteristic; t-tau, total tau.