25-Hydroxyvitamin D2 and D3
Test Mnemonic
D2D3
CPT Codes
- 82306 - QTY (1)
Includes
- 25-Hydroxy D2
- 25-Hydroxy D3
- 25-Hydroxy D Total
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Plasma | EDTA (Lavender) | Refrigerated | Centrifuge and transfer plasma/serum to a CCL tube and refrigerate. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Serum | No additive (Red) | Centrifuge and transfer plasma/serum to a CCL tube and refrigerate. | ||
| 1 mL | Plasma | EDTA (Navy Blue) | Centrifuge and transfer plasma/serum to a CCL tube and refrigerate. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 0.5 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 7 days |
| Refrigerated | 21 days |
| Frozen | 1 year |
Days Performed
2 days per week
Turnaround Time
1 - 6 days
Methodology
| Name | Description |
|---|---|
| Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) |
Reference Range
| 25-Hydroxy D Total | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Years | 99 Years | Normal | Deficient: < 20.1 | ng/mL | Years | 99 Years | Normal | Insufficient: 20.1 - 29.9 | ng/mL | Years | 99 Years | Normal | Sufficient: 30.0 - 100.0 | ng/mL | Years | 99 Years | Normal | Toxic: > 150.0 | ng/mL |
Special Info
In chronic kidney disease, parathyroid hormone levels should be monitored along with 25(OH)D for accurate treatment conditions. Patients with renal failure may have very high 25(OH)D2 and D3 levels without toxicity due to impaired renal conversion to the active 1,25-dihydroxyvitamin D. This test is not recommended for patients < 1 year old. Results may be falsely increased due to interfering substance present in patients < 1 year old.
Clinical Info
Vitamin D is crucial to bone health, calcium metabolism, and overall well-being. Vitamin D deficiency/insufficiency has been associated with poor bone metabolism, weak muscle strength, cancer risk and mortality, autoimmune disease, cardiovascular disease, and cystic fibrosis. Vitamin D3 is produced upon sunlight (specifically UVB) exposure to the skin. Minimal or no sun exposure and low dietary vitamin D intake commonly results in hypovitaminosis D (vitamin D insufficiency or deficiency). Monitoring vitamin D status is useful for detecting deficiency/insufficiency and for evaluating treatment efficacy in patients receiving vitamin D supplementation. 25-hydroxyvitamin D [25(OD)D] is the major circulating form of the vitamin and is the best indicator of vitamin D status. The liquid chromatography-mass spectrometry (LC-MS) assay method has high specificity and is able to separate 25(OH)D2 and 25(OH)D3 to yield independent values rather than just the total 25(OH)D. This vitamin D assay may be used to monitor vitamin D nutritional status, especially in patients with diseases that interfere with fat absorption such as cystic fibrosis and Crohn’s disease; in patients who have had gastric bypass surgery and may have impaired vitamin D absorption; or in patients with osteoporosis. The 25(OH)D levels are also used as an indicator of treatment effectiveness in patients being treated with vitamin D.