TABLE 4.
The effect of starting blood volume and DNA concentration methods on detection sensitivity in Rickettsia-spiked whole-blood and buffy coat samples
| Method | Sample type | Starting blood vol (μl) | Elution vol (μl) | Concn factor | LODa Rickettsia parkeri/ml in blood | LOD Rickettsia parkeri/μl in eluate |
|---|---|---|---|---|---|---|
| Qiagen blood minikit | Blood | 100 | 200 | 0.5 | 5,000 | 5.0 |
| Arrow v2 | Blood | 100 | 100 | 1.0 | 1,000 | 1.0 |
| Arrow v1 | Blood | 500 | 150 | 3.3 | 333 | 0.3 |
| MolYsis basic/Arrow v1 | Blood | 1,000 | 100 | 10.0 | 500 | 5.0 |
| QIAsymphony | Blood | 1,000 | 100 | 10.0 | 100 | 1.0 |
| Qiagen blood minikit | Blood | 200 | 200 | 1.0 | 5,000 | 0.2 |
| Qiagen blood minikit | Buffy coat | 1,000 | 200 | 5.0 | 100 | 0.1 |
a
LOD, limit of detection in Rickettsia parkeri Portsmouth strain.