Table 3.
Optimal plasma biomarker cut-offs with corresponding performance parameters for detecting amyloid-PET positivity
| Plasma ratio | Platform | Group | Cut-off | Sensitivity, % | Specificity, % | PPV, % | NPV, % |
|---|---|---|---|---|---|---|---|
| Age, APOE-ε4 | Total | na | 84 (69–94) | 46 (38–54) | 27 (23–31) | 93 (85–96) | |
| CN | na | 67 (45–84) | 65 (56–73) | 25 (19–33) | 92 (86–95) | ||
| aMCI | na | 79 (49–95) | 67 (45–84) | 58 (43–72) | 84 (65–94) | ||
| Aβ1–42/Aβ1–40 | ELISA | Total | < 0.159 | 78 (62–90) | 75 (68–82) | 42 (34–50) | 93 (88–96) |
| CN | < 0.159 | 78 (56–93) | 81 (74–87) | 41 (32–51) | 96 (91–98) | ||
| aMCI | < 0.170 | 86 (57–98) | 67 (45–84) | 60 (45–73) | 89 (68–97) | ||
| SIMOA | Total | < 0.230 | 74 (57–87) | 80 (72–86) | 46 (37–55) | 93 (88–96) | |
| CN | < 0.229 | 70 (47–87) | 79 (71–86) | 36 (27–46) | 94 (89–97) | ||
| aMCI | < 0.226 | 79 (49–95) | 88 (68–97) | 79 (55–92) | 88 (71–95) | ||
| Aβ1–42/t-tau | ELISA | Total | < 1.19 | 84 (68–94) | 64 (56–71) | 35 (30–41) | 95 (89–97) |
| CN | < 1.12 | 78 (56–93) | 69 (60–76) | 30 (23–37) | 96 (90–98) | ||
| aMCI | < 1.18 | 93 (66–100) | 79 (58–93) | 72 (54–85) | 95 (74–99) | ||
| SIMOA | Total | < 0.862 | 79 (63–90) | 68 (60–75) | 36 (30–43) | 93 (88–96) | |
| CN | < 0.899 | 83 (61–95) | 63 (54–71) | 27 (22–33) | 96 (90–99) | ||
| aMCI | < 0.815 | 79 (49–95) | 88 (68–97) | 79 (55–92) | 88 (71–95) |
aMCI amnestic mild cognitive impairment, Aβ β-amyloid, CN cognitively normal, NPV negative predictive value, PPV positive predictive value, t-tau total tau