Table 4 |.
Negative and positive predictive values of abnormal amyloid PET for plasma P-tau 181 and P-tau 217 by age group
| Subgroup | P-tau Cutpoint | A− | A+ | Prevalence | PPV | NPV |
|---|---|---|---|---|---|---|
| All (N=1051) | P-tau 181 <1.57 | 586 (92.0%) | 201 (48.6%) | 414/1051 (39.4%) | 213/264 (80.7%) | 586/787 (74.5%) |
| P-tau 181 >=1.57 | 51 (8.0%) | 213 (51.4%) | ||||
| P-tau 217 <0.25 | 614 (96.4%) | 203 (49.0%) | 414/1051 (39.4%) | 211/234 (90.2%) | 614/817 (75.2%) | |
| P-tau 217 >=0.25 | 23 (3.6%) | 211 (51.0%) | ||||
|
| ||||||
| <70 years (N=338) | P-tau 181 <1.57 | 286 (97.6%) | 37 (82.2%) | 45/338 (13.3%) | 8/15 (53.3%) | 286/323 (88.5%) |
| P-tau 181 >=1.57 | 7 (2.4%) | 8 (17.8%) | ||||
| P-tau 217 <0.25 | 291 (99.3%) | 37 (82.2%) | 45/338 (13.3%) | 8/10 (80.0%) | 291/328 (88.7%) | |
| P-tau 217 >=0.25 | 2 (0.7%) | 8 (17.8%) | ||||
|
| ||||||
| 70–77 years (N=261) | P-tau 181 <1.57 | 146 (90.7%) | 49 (49.0%) | 100/261 (38.3%) | 51/66 (77.3%) | 146/195 (74.9%) |
| P-tau 181 >=1.57 | 15 (9.3%) | 51 (51.0%) | ||||
| P-tau 217 <0.25 | 155 (96.3%) | 59 (59.0%) | 100/261 (38.3%) | 41/47 (87.2%) | 155/214 (72.4%) | |
| P-tau 217 >=0.25 | 6 (3.7%) | 41 (41.0%) | ||||
|
| ||||||
| 78–83 years (N=242) | P-tau 181 <1.57 | 97 (89.0%) | 64 (48.1%) | 133/242 (55.0%) | 69/81 (85.2%) | 97/161 (60.2%) |
| P-tau 181 >=1.57 | 12 (11.0%) | 69 (51.9%) | ||||
| P-tau 217 <0.25 | 101 (92.7%) | 60 (45.1%) | 133/242 (55.0%) | 73/81 (90.1%) | 101/161 (62.7%) | |
| P-tau 217 >=0.25 | 8 (7.3%) | 73 (54.9%) | ||||
|
| ||||||
| 84+ years (N=210) | P-tau 181 <1.57 | 57 (77.0%) | 51 (37.5%) | 136/210 (64.8%) | 85/102 (83.3%) | 57/108 (52.8%) |
| P-tau 181 >=1.57 | 17 (23.0%) | 85 (62.5%) | ||||
| P-tau 217 <0.25 | 67 (90.5%) | 47 (34.6%) | 136/210 (64.8%) | 89/96 (92.7%) | 67/114 (58.8%) | |
| P-tau 217 >=0.25 | 7 (9.5%) | 89 (65.4%) | ||||
*
Abnormal amyloid PET (A+) was defined as standard uptake value ratio (SUVR)>1.48 using PiB-PET. PPV, positive predictive value; NPV, negative predictive value.