Table 1.
Limit of Detection (LOD) of Spiked Filovirus Recombinant Viral Protein 40 (VP40) Antigen in Serum and Whole-Blood Specimens
| VP40 Antigen Level |
Replicates, Proportiona | Result | |
|---|---|---|---|
| ng/mL | ng/Test | ||
| Preliminary | |||
| 10 000 | 300 | 5/5 | Positive |
| 5000 | 150 | 5/5 | Positive |
| 2500 | 75.0 | 5/5 | Positive |
| 1250 | 37.5 | 5/5 | Positive |
| 625 | 18.8 | 5/5 | Positive |
| 312 | 9.4 | 5/5 | Positive |
| 160 | 4.7 | 5/5 | LOD |
| 80 | 2.3 | 3/5 | Negative |
| 40 | 1.2 | 0/5 | Negative |
| Serum confirmation | |||
| 160 | 4.7 | 20/20 | LOD |
| 80 | 2.3 | 18/20 | … |
| Whole-blood confirmation | |||
| 312 | 9.4 | 18/20 | LOD |
| 160 | 4.7 | 13/20 | … |
| Blank control | 0/5 | Negative | |
a Data are no. of positive whole-blood specimens/no. tested.