25‑Hydroxyvitamin D, Immunoassay
Also known as: 25 OH Vitamin D, Vitamin D, 25-OH, 25-Hydroxy Vitamin D, Vitamin D
Use
Measurement of total 25‑hydroxyvitamin D [25(OH)D] concentrations in serum provides a good index of circulating vitamin D activity. It is used to screen patients not on vitamin D₂ supplementation for vitamin D deficiency or insufficiency, which can lead to bone diseases such as rickets and osteomalacia, or complications like hypercalcemia. Ideal ranges (30–100 ng/mL) indicate optimal status, below suggests deficiency or insufficiency, and above may reflect toxicity.
Special Instructions
Immunoassay method provides reliable quantitative total 25(OH)D results suitable for most patients. It offers fast turnaround—typically results available the next day. It does not differentiate between D₂ and D₃ and is not impacted by the C3‑epimer, unlike LC‑MS/MS methods. Recommended when patients are not on D₂ prescription supplementation.
Limitations
This immunoassay does not differentiate or measure individual 25‑hydroxyvitamin D₂ and D₃ isomers, nor does it detect or correct for the C3‑epimer form. It may overestimate total vitamin D in patients with D₂ supplementation or in infants with significant C3‑epimer levels, for which LC‑MS/MS methods are preferred.
Methodology
Immunoassay
Biomarkers
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
Not provided
Minimum Volume
Not provided