Table 4. Back calculated accuracy and precision levels of calibration standards and spiked samples during the validation.
| Analyte | Calibration standards Recovery ±s (concentration) | Spiked samples Recovery ±s (spiked concentration)a | ||||
| Low | Medium | High | Low | Medium | High | |
| p-Tyr | 122±4 (0.8 μM) | 86±4 (12.5 μM) | 95±1 (150 μM) | 90±5 (110 μM) | 111±3 (140 μM) | 123±2 (170 μM) |
| m-Tyr | 98±6 (31 nM) | 100±5 (125 nM) | 98.9±0.6 (188 nM) | 86±1.6 (80 nM) | 90.0±0.5 (130 nM) | 97±3 (200 nM) |
| o-Tyr | 103±9 (31 nM) | 95±3 (250 nM) | 99±3 (750 nM) | 96±4 (200 nM) | 100.2±0.5 (475 nM) | 100.7±0.8 (725 nM) |
| Phe | 109±4 (0.4 μM) | 100±2 (12.5 μM) | 99±1 (150 μM) | 98±2 (60 μM) | 100.6±0.2 (115 μM) | 100.8±0.7 (170 μM) |
| 3NO2-Tyr | 104±9 (31 nM) | 93±7 (250 nM) | 98±3 (750 nM) | 77±4 (180 nM) | 93±5 (455 nM) | 91.6±0.3 (725 nM) |
| 3Cl-Tyr | 107±6 (16 nM) | 89±3 (250 nM) | 99±3 (1500 nM) | 99.8±1.5 (180 nM) | 100.3±0.8 (910 nM) | 101.0±0.9 (1600 nM) |
| 2-dG | 109±8 (16 nM) | 88±5 (125 nM) 9.70 | 98±2 (750 nM) | 99±1 (250 nM) | 103±1 (530 nM) | 101±2 (725 nM) |
| 8OHdG | 106±10 (4 nM) | 88±8 (31 nM) | 98±3 (188 nM) | 67±3 (80 nM) | 81±2 (120 nM) | 81±6 (190 nM) |
a
: concentrations in the spiked samples were calculated after subtracting the mean levels (n = 3) measured in the non-spiked pooled urine samples during each validation batch.