Table 3.
Intra-plate imprecision (n=7) for JWH-018 N-(5-hydroxypentyl) concentrations (1–10 µg/L). Inter-plate imprecision (n=35) for JWH-018 metabolite using positive controls (10 & 20µg/L) and performance challenge concentrations at ±25% and ±50% of each cutoff. Inter-read imprecision for a representative calibration curve (1–500µg/L) for JWH-018 N-(5-hydroxypentyl) in urine.
| Urine JWH-018 metabolite µg/L |
Intra-plate (n=7) Absorbance % |
Inter-plate (n=35) Absorbance % |
Inter-read (n=7) Absorbance % |
|||
|---|---|---|---|---|---|---|
| Mean (SD) | CV | Mean (SD) | CV | Mean (SD) | CV | |
| 1 | 0.827 (0.051) | 6.2 | - | - | 0.902 (0.024) | 2.7 |
| 2.5 | 0.613 (0.027) | 4.2 | 0.787 (0.092) | 11.6 | 0.727 (0.020) | 2.8 |
| 3.75 | - | - | 0.630 (0.079) | 12.5 | - | - |
| 5 | 0.511 (0.036) | 7.0 | 0.594 (0.067) | 11.2 | 0.474 (0.015) | 3.2 |
| 6.25 | - | - | 0.557 (0.067) | 12.0 | - | - |
| 7.5 | 0.469 (0.038) | 8.2 | 0.555 (0.078) | 14.0 | 0.407 (0.014) | 3.5 |
| 10 | 0.327 (0.020) | 5.5 | 0.388 (0.035) | 9.0 | 0.374 (0.011) | 3.1 |
| 12.5 | - | - | 0.351 (0.035) | 10.0 | - | - |
| 15 | - | - | 0.321 (0.031) | 9.8 | - | - |
| 20 | - | - | 0.284 (0.037) | 13.0 | - | - |
| 25 | - | - | - | - | 0.222 (0.007) | 3.3 |
| 50 | - | - | - | - | 0.157 (0.006) | 3.7 |
| 100 | - | - | - | - | 0.118 (0.005) | 4.0 |
| 250 | - | - | - | - | 0.087 (0.003) | 3.7 |
| 500 | - | - | - | - | 0.070 (0.001) | 2.1 |