Laboratory Medicine
Test Directory / Vitamin D
Vitamin D
Brown clotted serum, gel barrier
| Test | Vitamin D |
|---|---|
| Common Abbreviations | 25-OH VITD |
| Profile | NA |
| Tube type | Brown clotted serum, gel barrier |
| Clinical Indication | Vitamin D is primarily requested for the investigation of metabolic bone disease. Other indications may include hyperparathyroidism, patients with tuberculosis, individuals on anticonvulsant therapy, subjects on anti-retroviral therapy and those with CKD or nephrotic syndrome. |
| Specimen Type | Blood |
| Sample type | Serum |
| Minimum Volume | 0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample. |
| Special Precautions | No special requirements |
| Stability | 72 hours at 20 - 25°C, 4 days at 2 - 8°C and 24 weeks at -20°C |
| Turnaround Time | Inpatient: 24 hours Outpatient/ GP: 24 hours |
| Laboratory | York and Scarborough |
| Reference Interval | >50 nmol/L - replete - no treatment required 30-50 nmol/L - indicates insufficiency - treatment advised if symptomatic <30 nmol/L - indicates deficiency - treatment recommended |
| Limitations | Analysis should not be performed on grossly haemolysed, icteric or lipaemic samples. The assay is unaffected by biotin < 2456 nmol/L or < 600 ng/mL. Samples should not be taken from patients receiving therapy with high biotin doses. Some studies have shown that serum concentrations of biotin can reach up to 355 ng/mL within the first hour after biotin ingestion for subjects consuming supplements of 20 mg biotin per day. In vitro tests were performed on 17 commonly used pharmaceuticals. No interference with the assay was found. In rare cases, interference due to extremely high titres of antibodies to analyte-specific antibodies, streptavidin or ruthenium can occur. These effects are minimized by suitable test design. For diagnostic purposes, the results should always be assessed in conjunction with the patientÂ’s medical history, clinical examination and other findings. |
| Notes |
