Synonyms: 25-hydroxyvitamin-D3 (25OH-D3), 25-hydroxycholecalciferol, calcifediol, calcidiol; 25-hydroxyvitamin-D2 (25OH-D2), 25-hydroxyergocalciferol.
What is measured: 25-hydroxyvitamin-D3 and 25-hydroxyvitamin-D2.
Performance of the assay
Lower limit of detection (LOD) (25OH-D3/25OH-D2): 3.3/3.3 nmol/L.
Within-day CV: 4-5/4-5 %; between-day CV: 7-8/5-8 %.
Assessment of vitamin D status.
Specimen, collection and processing
Patient/subject: Vitamin D levels show a high level of seasonality due to the influence of sunlight.
Matrix: Serum or EDTA plasma.
Volume: Minimum volume is 50 µL, but 200 µL is optimal and allows reanalysis.
Preparation and stability: Samples should be put on ice, and protected from light.
Transportation; for general instruction on transportation, click here.
Frozen, on dry ice.
Reported values, interpretation
Reported values (25OH-D3/25OH-D2): 20-150/0-4 nmol/L.
Intraclass correlation coefficient (ICC) (25OH-D3/25OH-D2): 0.71/na.