Table 2.
Thresholds for plasma pTau217, pTau181 and Aβ1–42/Aβ1–40 to detect A + participants
| Threshold | Sensitivity | Specificity | NPV | PPV | Youden | Accuracy |
|---|---|---|---|---|---|---|
| Accuracy of plasma pTau217 | ||||||
| 0.130 | 97.8% | 65.5% | 96.9% | 73.1% | 0.634 | 81.3% |
| 0.186 | 95.0% | 82.1% | 94.4% | 83.5% | 0.770 | 88.4% |
| 0.247 | 90.6% | 89.7% | 90.9% | 89.4% | 0.803 | 90.1% |
| 0.249 | 89.9% | 89.7% | 90.3% | 89.3% | 0.796 | 89.8% |
| 0.388 | 69.8% | 95.2% | 76.7% | 93.3% | 0.650 | 82.7% |
| 0.552 | 45.3% | 97.2% | 65.0% | 94.0% | 0.426 | 71.8% |
| Accuracy of plasma pTau181 | ||||||
| 1.573 | 97.9% | 32.0% | 94.1% | 57.3% | 0.299 | 63.8% |
| 1.740 | 95.0% | 44.7% | 90.5% | 61.6% | 0.397 | 69.0% |
| 2.125 | 90.0% | 71.3% | 88.4% | 74.6% | 0.613 | 80.3% |
| 2.815 | 64.3% | 90.0% | 73.0% | 85.7% | 0.543 | 77.6% |
| 3.345 | 47.9% | 94.7% | 66.0% | 89.3% | 0.425 | 72.1% |
| 3.840 | 31.4% | 97.3% | 60.3% | 91.7% | 0.288 | 65.5% |
| Accuracy of Aβ1–42/Aβ1–40 | ||||||
| 0.086 | 97.9% | 41.3% | 95.4% | 60.9% | 0.392 | 68.6% |
| 0.080 | 95.0% | 65.3% | 93.3% | 71.9% | 0.603 | 79.7% |
| 0.078 | 90.0% | 75.3% | 89.0% | 77.3% | 0.653 | 82.4% |
| 0.073 | 65.0% | 90.0% | 73.4% | 85.8% | 0.550 | 77.9% |
| 0.070 | 37.9% | 94.7% | 62.0% | 86.9% | 0.325 | 67.2% |
| 0.067 | 20.7% | 97.3% | 56.8% | 87.9% | 0.180 | 60.3% |
pTau217: phosphorylated tau 217, pTau181: phosphorylated tau 181. Aβ1–42: Amyloid β1–42. Aβ1–40: Amyloid β1–40. NPV, negative predictive value. PPV, positive predictive value. Threshold units for pTau are in pg/mL