Extended Data Table 1.
Spike recovery - analytical validation of the accuracies of the new p-tau212 assay to quantify signal from an exogenous source (spike) added to a primary sample.
| CSF Recovery | ||||||
|---|---|---|---|---|---|---|
| Analyte | Observed conc. (pg/ml) | Expected Concentration (pg/ml) | %CV conc. | % recovery | ||
| Measured | Mean | |||||
| Sample 1 | Neat | 10.857 10.943 |
10.9 | 0.5 | ||
| + high spike | 35.324 40.416 |
37.87 | 39.14 | 9.5 | 96.7 | |
| + low spike | 20.727 20.481 |
20.06 | 20.98 | 0.8 | 98.2 | |
| Sample 2 | Neat | 11.496 13.387 |
12.44 | 10.7 | ||
| + high spike | 35.908 33.449 |
34.68 | 40.68 | 5 | 85.3 | |
| + low spike | 21.332 25.087 |
23.21 | 22.52 | 11.4 | 103.1 | |
| Buffer control | Buffer + high spike | 28.339 28.135 |
28.24 | 0.5 | ||
| Buffer + low spike | 9.801 10.351 |
10.08 | 3.9 | |||
| Plasma Recovery | ||||||
| Treatment | Observed conc. (pg/ml) | Expected Concentration (pg/ml) | %CV conc. | % recovery | ||
| Measured | Mean | |||||
| Sample 1 | Neat | 0.593 0.837 |
0.715 | 24.1 | ||
| + high spike | 0.881 | 1.02 | 1.119 | 19.2 | 86.0 | |
| 1.158 | ||||||
| + low spike | 0.859 0.892 |
0.875 | 0.997 | 2.7 | 82.9 | |
| Buffer control for Sample 1 | Buffer + high spike | 0.453 0.356 |
0.404 | 17.0 | ||
| Buffer + low spike | 0.311 0.254 |
0.282 | 14.5 | |||
| Sample 2 | Neat | 1.634 1.946 |
1.790 | 12.3 | ||
| + high spike | 3.114 3.115 |
3.115 | 3.481 | 0.0 | 79.6 | |
| + low spike | 2.473 2.334 |
2.404 | 2.511 | 4.1 | 94.0 | |
| Buffer control for Sample 2 | Buffer + high spike | 1.534 1.848 |
1.691 | 13.1 | ||
| Buffer + low spike | 0.623 0.820 |
0.721 | 19.3 | |||
*
Expected concentration was calculated as the sum of the sample and spike levels analyzed separately. The measured concentration is the response obtained for the true analyte concentration in the spiked sample.
#
% recovery is the fraction of the measured to the expected concentration × 100%.