Table 3.
Precision and accuracy, recovery and matrix effects data for SIR-2 in plasma.
| LLOQ QC | Low QC | Low-Medium QC | Medium QC | High QC | Dilution QC | ||
|---|---|---|---|---|---|---|---|
| Hybrid LC-MS | Nominal concentration (ng/ml) | 0.200 | 0.600 | 8.00 | 80.0 | 160 | 10000† |
| Precision and accuracy | 7.67 (28.8) | 3.19 (13.7) | 9.60 (6.20) | 14.3 (8.81) | -2.62 (6.22) | -22.6 (7.40) | |
| Recovery (%) | N/A | 88.5 ± 20.4 | N/A | 103 ± 6.48 | 103 ± 10.0 | N/A | |
| Matrix factor‡ | N/A | 1.09 ± 0.32 | N/A | 1.06 ± 0.07 | 0.92 ± 0.09 | N/A | |
| SL-RT-qPCR | Nominal concentration (ng/ml) | 0.128 | 0.500 | 2.50 | 50.0 | 1000 | 5000† |
| Precision and accuracy | 5.25 (7.95) | 18.6 (7.50) | 14.9 (7.94) | 20.1 (7.69) | -14.5 (8.70) | -5.96 (10.9) | |
| HELISA | Nominal concentration (ng/ml) | 1.00 | 3.00 | N/A | 30.0 | 200 | 10000† |
| Precision and accuracy | -4.93 (5.80) | -0.648 (15.3) | N/A | 11.5 (15.7) | 11.6 (6.09) | 7.62 (12.7) | |
| SPE-LC-MS | Nominal concentration (ng/ml) | 5.00 | 15.0 | N/A | 200 | 400 | 10000† |
| Precision and accuracy | 6.60 (8.53) | 23.0 (17.1) | N/A | -6.62 (15.4) | 13.7 (24.0) | -18.7 (14.1) | |
| Recovery (%) | N/A | 43.4 ± 11.4 | N/A | 31.7 ± 4.39 | 36.4 ± 13.6 | N/A | |
| Matrix factor‡ | N/A | 1.02 ± 0.12 | N/A | 0.94 ± 0.09 | 1.13 ± 0.33 | N/A |
Samples were diluted 100× with control plasma prior to analysis.
Determined by comparing to signals in post-extraction spiked plasma samples to post-extraction spiked water samples, which is a relative assessment of matrix effects. Absolute matrix effects which also consider the impact of reagents used during sample preparation may be different from this value.
Data are presented as %Bias (%CV) or as Arithmetic Mean ± Standard Deviation (n = 6 for each QC level, except for the dilution QC where n = 3).
HELISA: Hybridization ELISA; LLOQ: Lower limit of quantitation; N/A: Not applicable; QC: Quality control; SL-RT-qPCR: Stem-loop reverse transcription quantitative PCR; SPE: Solid-phase extraction.