New in-house test - 1,25 dihydroxy vitamin D

Published on : 10 September 2017
Location : Abu Dhabi.

We are proud to announce that we have recently expanded our in-house test menu with a 1,25 dihydroxy vitamin D test, performed at our laboratory in ICAD, Abu Dhabi.

Below please find more information about the test:

Order Code

Order Code Name

CPT Code

Specimen type

Volume

Specimen container

Storage

Specimen Stability

081091

 1,25 Dihydroxy Vitamin D, Serum

 82652

 Serum

 1.0 mL

Gel-barrier tube 

Refrigerate 

14 days at 2°C to 8°C 

 

  • Specimen type: Serum
  • Specimen Container: Red-top or gel-barrier serum tube
  • Storage: Refrigerated
  • Testing Frequency: Monday and Wednesday 
  • TAT: 3-5 days
  • Clinical significance

Vitamin D is essential in the body for regulating the absorption of calcium and for promoting healthy bone formation and maintenance. It has also been shown to have a positive impact on the immune system and other cellular processes.

The two most important forms for detecting vitamin D deficiency are 25-hydroxy vitamin D3 and 25-hydroxy vitamin D2. Vitamin D3 (‘Human or animal form’, cholecalcifedol) is mainly produced in the skin after sun exposure but can also be taken up through food, while vitamin D2 (‘plant form’, ergocalcifedol) can be obtained only from fortified food and supplements. Both forms are metabolized in the liver to the inactive form 25-hydroxy vitamin D and stored until needed, at which point 25-hydroxy vitamin D is converted in the kidneys to the active form  1,25-dihydroxy vitamin D. Although  1,25-dihydroxy vitamin D is the active form, it does not reflect vitamin D deficiency as it is tightly regulated by PTH, Calcium and Phosphate. The concentration of total 25-hydroxy vitamin D in the serum reflects the stored supply of all vitamin D (D2 + D3) and gives a good indication of the vitamin D deficiency status of the patient.

However, in the presence of renal disease or other medical conditions (insufficiency, dialysis etc.), 1,25-dihydroxy vitamin D levels may be needed to adequately assess vitamin D status.

1,25-dihydroxy vitamin D levels may be high in :

  • primary hyperparathyroidism
  • physiologic hyperparathyroidism secondary to low calcium or vitamin D intake
  • granulomatous diseases (e.g. sarcoidosis)
  • malignancies containing nonregulated 1-alpha hydroxylase in the lesion may have elevated 1,25-dihydroxy vitamin D levels and cause hypercalcemia.