Table 2.
Method performance.
| Vitamin D metabolite | LLoQ nmol/L | Intra-assay CV% (nmol/L)a | Inter-assay CV% (nmol/L)b | Bias % (nmol/L)b |
|---|---|---|---|---|
| 25OHD3 | 7.0 | 3.34 (40.6) | 5.3 (38.4) | 1.4 (37.9) |
| 0.79 (95.2) | 4.3 (91.7) | 4.8 (87.5) | ||
| 25OHD2 | 5.0 | 4.02 (40.4) | 5.9 (46.8) | 11.2 (42.1) |
| 1.09 (93.6) | 3.8 (113.1) | 4.7 (108.0) | ||
| 3-epi-25OHD3 | 4.0 | 2.07 (36.2) | 6.0 (39.3) | 14.9 (34.2) |
| 2.32 (61.0) | 3.7 (67.5) | 23.8 (54.5) |
LLoQ: Lower limit of quantification.
a
5 sequential injections of each concentration of the MassCheck® controls were performed. Values in parentheses are the means.
b
1 aliquot of each concentration of the MassCheck® controls was analyzed over a period of 14 consecutive months [n=90]. For the inter-assay repeatability, values in parentheses are those obtained by our method. For the bias, values in parentheses are those assigned by the manufacturer.