Table 2.
The validation data for quantification of the four VitD metabolites in serum.
| VitD metabolites | Nominal concentration (pg/mL) | Intra-day (n=6) | Inter-day (n=6) | ||||
|---|---|---|---|---|---|---|---|
| Calculated concentration [Mean ± SD, (pg/mL)] | Relative error (%) | % CV | Calculated concentration [Mean ± SD, (pg/mL)] | Relative error (%) | % CV | ||
| Blank QCsa | |||||||
| 1,25(OH)2D3 | 1.0 | 0.95 ± 0.05 | − 5 | 5.3 | 1.12 ± 0.07 | 12 | 6.3 |
| 6.0 | 5.9 ± 0.3 | − 2 | 4.6 | 6.2 ± 0.5 | 3 | 8.0 | |
| 40.0 | 42.6 ± 4.5 | 7 | 10.6 | 38.5 ± 4.4 | − 4 | 11.0 | |
| 200.0 | 206.0 ± 7.9 | 3 | 3.9 | 204.7 ± 10.9 | 2 | 8.7 | |
| 24,25(OH)2D3 | 5.0 | 5.2 ± 0.5 | 4 | 9.6 | 4.9 ± 0.6 | −2 | 11.2 |
| 30.0 | 31.4 ± 3.1 | 5 | 10.0 | 30.7 ± 1.9 | 2 | 6.4 | |
| 200.0 | 209.2 ± 11.0 | 5 | 5.3 | 218.2 ± 10.9 | 9 | 5.0 | |
| 1000.0 | 1046.9 ± 70.2 | 3 | 7.2 | 1044.2± 75.1 | 4 | 7.2 | |
| 25(OH)D3 | 30.0 | 31.2 ± 2.8 | 4 | 8.8 | 28.9 ± 3.9 | − 4 | 13.4 |
| 1000.0 | 1020.0 ± 83.1 | 2 | 8.1 | 960.0 ± 63.4 | 2 | 6.6 | |
| 6670.0 | 6620.2 ± 290.3 | − 1 | 4.4 | 6280.7 ± 500.1 | − 6 | 8.0 | |
| 33300.0 | 33605.3 ± 1190.1 | 1 | 3.5 | 32823.6 ± 515.6 | − 1 | 1.6 | |
| 25(OH)D2 | 30.0 | 30.7 ± 3.6 | 2 | 11.6 | 29.8 ± 3.0 | − 1 | 10.0 |
| 200.0 | 190.7 ± 8.8 | − 6 | 4.6 | 183.5 ± 13.8 | − 8 | 7.5 | |
| 1330.0 | 1244.1 ± 93.9 | − 6 | 7.5 | 1271.7 ± 64.4 | − 5 | 5.1 | |
| 6670.0 | 6412.6 ± 210.2 | − 4 | 3.3 | 6152.9 ± 229.8 | − 8 | 3.7 | |
| Fortified QCsb,c | |||||||
| 1,25(OH)2D3 | 16.7 | 15.2 ± 0.9 | − 9 | 5.6 | 15.5 ± 0.6 | − 7 | 4.1 |
| 50.0 | 48.5 ± 2.3 | − 3 | 4.7 | 46.5 ± 0.3 | − 7 | 0.7 | |
| 24,25(OH)2D3 | 250.0 | 275.0 ± 1.7 | 10 | 0.6 | 272.5 ± 22.1 | 9 | 8.1 |
| 750.0 | 832.5 ± 44.1 | 11 | 5.3 | 742.5 ± 84.6 | − 1 | 11.4 | |
| 25(OH)D3 | 1670.0 | 1603.2 ± 89.8 | − 4 | 5.6 | 1586.5 ± 128.5 | − 5 | 8.1 |
| 5000.0 | 4600.0 ± 317.4 | − 8 | 6.9 | 5150.0 ± 170.0 | 3 | 3.3 | |
| 25(OH)D2 | 1670.0 | 1569.8 ± 168.0 | − 6 | 10.7 | 1653.3 ± 77.7 | − 1 | 4.7 |
| 5000.0 | 4900.0 ± 137.3 | − 2 | 2.8 | 4750.0 ± 427.5 | − 5 | 9.0 | |
aPrepared by spiking standard compounds into blank matrix.
bPrepared by spiking standard compounds into a pooled human serum.
cThe endogenous level has been subtracted from the measured value.