Table 2.
Demographics for 6,192 clinical specimensa submitted for Aβ42/40 testing.
| Age, years | N total, % female | Aβ42 mean, pg/mL (SD) | Aβ40 mean, pg/mL (SD) | Aβ42/40 mean (SD) | Aβ42/40 < 0.160, N, % (indeterminant/high risk of PET positivity) | Aβ42/40 ≥ 0.170, N, % (likely PET negative) |
|---|---|---|---|---|---|---|
| <40 | 83, 65% | 38.7 (8.3) | 207.3 (43.5) | 0.188 (0.021) | 3, 4% | 69, 83%, |
| 40 to 49 | 162, 62% | 38.2 (8.6) | 210.4 (42.4) | 0.182 (0.023) | 20, 12%, | 116, 72%, |
| 50 to 59 | 582, 63% | 40.5 (10.6) | 228.7 (57.2) | 0.178 (0.024) | 138, 24%, | 369, 63%, |
| 60 to 69 | 1,370, 58% | 40.6 (10.5) | 241.7 (58.5) | 0.169 (0.023) | 497, 36% | 631, 46%, |
| 70 to 79 | 2,451, 57% | 42.9 (11.9) | 264.7 (71.0) | 0.163 (0.022) | 1,157, 47% | 863, 35%, |
| 80 to 89 | 1,417, 54% | 45.5 (12.5) | 284.9 (77.8) | 0.161 (0.021) | 713, 50% | 436, 31%, |
| ≥ 90 | 127, 60% | 48.1 (10.7) | 304.5 (74.0) | 0.159 (0.019) | 68, 54%, | 32, 25%, |
| All | 6,192, 57% | 42.7 (11.7) | 259.4 (71.3) | 0.166 (0.023) | 2,596, 42%, | 2,516, 41%, |
Aβ, beta-amyloid; PET, positron emission tomography. aThis was a limited dataset with only patient age and sex available.