Table 1. Precision studies for all 25(OH)D immunoassays tested.
| Assay | QC material* | Within-run | Between-run | ||||
|---|---|---|---|---|---|---|---|
|
Mean (ng/mL)† |
SD‡ |
CV (%)§ |
Mean (ng/mL) |
SD |
CV (%) |
||
| IDS-iSYS 25(OH)D | Low-level | 7.7 | 1.2 | 15.5 | 9.4 | 1.8 | 19.1 |
| Mid-level | 38.8 | 3.9 | 10.5 | 3.9 | 3.9 | 10.0 | |
| High-level | 66.8 | 4.1 | 6.1 | 65.5 | 4.9 | 7.4 | |
| IDS-iSYS 25(OH)DS | Low-level | 15.2 | 2.9 | 19.0 | 9.8 | 1.6 | 16.3 |
| Mid-level | 48.7 | 4.5 | 9.0 | 49.5 | 5.5 | 11.1 | |
| High-level | 78.1 | 5.9 | 7.5 | 78.2 | 6.8 | 8.6 | |
| ORGENTEC 25(OH)D3/D2 | Low-level | 19.2 | 1.2 | 6.3 | 16.6 | 1.1 | 6.6 |
| Mid-level | 38.8 | 4.8 | 12.3 | 35.6 | 2.1 | 5.8 | |
| High-level | 60.3 | 3.6 | 5.9 | 62.3 | 1.9 | 3.0 | |
*Quality control material of the assay manufacturers; †mean concentration in nanograms per milliliter (ng/mL x 2.5 = nmol/L); ‡standard deviation; §coefficient of variation in percent.