Table 2.
Summarized results of the validation of DBS analysis
| Validation criterion | Validation level (n = 5)e |
|||
|---|---|---|---|---|
| LLOQ | Low | Medium | High | |
| Nominal linezolid concentration (mg/liter) | 0.05 | 0.25 | 15 | 30 |
| Reproducibilitya | ||||
| Accuracy (bias [%]) | 4.5 | 6.3 | 3.2 | −1.3 |
| Within-day precision (CV [%]) | 13.8 | 4.0 | 4.1 | 1.6 |
| Between-day precision (CV [%]) | 10.2 | 3.5 | 6.1 | 7.7 |
| Overall precision (CV [%]) | 17.2 | 5.3 | 7.4 | 7.8 |
| Matrix effect (%) | 2.9 | 8.7 | 1.9 | |
| Recovery (%) | 95.5 | 94.1 | 97.2 | |
| Effect of blood vol (range of bias [%])b | −2.9–4.1 | −11.4–7.1 | −11.6–9 | |
| Effect of hematocrit (range of bias [%])c | −17.8–11.9 | −7.6–6.8 | −12.5–5.7 | |
| Stabilityd | ||||
| 1 week at 50°C (bias [%]) | 6.7 | −3.4 | ||
| 2 mos at 37°C (bias [%]) | −10 | −5.9 | ||
| 2 mos at ambient temp (bias [%]) | −2.5 | −2.0 | ||
a
Data are from three separate validation days.
b
Comparison with sample of standardized blood spot volume (35 μl).
c
Comparison with samples of standardized hematocrit (35%).
d
Present data are from the last time point of the stability test only.
e
n, number of replicates.