Table 4.
Proposed plasma Aβ42/40 ranges for clinical decision making. Percentage of individuals falling within a range unless otherwise specified. Real world projections of positive emission tomography (PET) positivity are based on percent PET positivity in the Alzheimer’s Disease Research Center (ADRC) cohort.
| Plasma Aβ42/40 Range | Designation | ADRC, N (% of cohort) | PET positivity, N (%) | MCI, N (%) | AD, N (%) | ApoE4, N (%) | Real world, N (% of cohort) | Real world, projections of PET positivity, N | Potential next evaluation and management considerations |
|---|---|---|---|---|---|---|---|---|---|
|
| |||||||||
| <0.150 | Positive (low ratio) | 91 (36.4) | 61 (67.0) | 50 (54.9) | 34 (37.4) | 43 (47.3) | 1468 (23.7) | 984 | Follow up for AD workup (high risk) |
| 0.150-0.159 | Indeterminant (lower ratio) | 37 (14.8) | 31 (83.8) | 14 (37.8) | 18 (48.7) | 25 (67.6) | 1128 (18.2) | 945 | Follow up for AD workup (indeterminant risk) |
| 0.160-0.169 | Indeterminant (higher ratio) | 38 (15.2) | 7 (18.4) | 19 (50.0) | 2 (5.3) | 7 (18.4) | 1080 (17.4) | 199 | Follow up for AD workup (low risk) |
| ≥0.170 | Negative (high ratio) | 84 (33.6) | 2 (2.4) | 41 (48.8) | 0 (0.0) | 13 (15.5) | 2516 (40.6) | 60 | Follow up for non- AD etiology |
| All | All | 250 | 101 (40.4) | 124 (49.6) | 54 (21.6) | 88 (35.2) | 6192 | 2188 | |