1,25-Dihydroxyvitamin D, Serum
Use
This test is a second-order assessment tool to determine vitamin D status in patients, especially those with renal disease. It aids in the investigation of suspected vitamin D deficiency cases, such as vitamin D-dependent rickets caused by hereditary deficiencies or end-organ resistance. It is also essential in the differential diagnosis of hypercalcemia, aiding in determining underlying causes.
Special Instructions
Fasting for 4 hours is preferred but not required before specimen collection. If not ordering electronically, complete and send a General Request or Renal Diagnostics Test Request form with the specimen.
Limitations
1,25-Dihydroxyvitamin D levels are not suitable as direct indicators of vitamin D toxicity, as low results may still occur in cases of toxicity. Gross hemolysis is a reason for specimen rejection, while gross lipemia or icterus does not affect the acceptability of a specimen. The reported reference intervals may not be applicable if converted to different units.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 62290-2
- 62290-2
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.5 mL
Minimum Volume
0.7 mL
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial.
Patient Preparation
Fasting: 4 hours, preferred but not required
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 30 days |
| Frozen | 30 days |