Dihydroxy Vitamin D

The 1,25 Dihydroxy-Vitamin D blood test is conducted to identify the Vitamin D levels in your body and whether you have received it the right level of supplement. The test is conducted on a blood sample drawn from the vein. There is no preparation time or regime required. The test is sometimes called the Calcitriol Test

Who is tested for vitamin D levels

The National Osteoporosis Foundation advises that (1) older women (2) women with dark skin (3) institutionalized women and (4) women detected with malabsorption of Vitamin D should undergo this blood test. 

Besides, other people who need to take the test are those who show evidences of

  • Bone abnormalities like weakness, chronic pain and stress, inflammation
  • Bone malformation in children on the onset of rickets
  • Higher levels of calcium
  • Higher levels of phosphorus
  • Higher levels of parathyroid hormone

The test is also conducted if the health care provider feels that you may be suffering from Vitamin D deficiency. Others who undergo the test include those who are about to begin a treatment regime for osteoporosis and those being monitored for the deficiency of Vitamin D.

Other indications for which this test is advised are

  • Testing for Vitamin D sufficiency in patients affected with Crohn’s disease
  • Monitoring of diseases that interfere with fat absorption like cystic fibrosis
  • Monitoring the efficacy of prescribed supplements of magnesium, calcium and/or phosphorus

Reference range for vitamin d test

There is no standard reference range for diagnosis in this test. The result is dependent on various dynamic parameters like the patient’s age, metabolism, immune system, efficacy of supplement absorption, nature of specific disease, and severity of symptoms and so on.


The result of the test should be thoroughly discussed with the doctor who will be able to gauge the future treatment regimen. Some indications of the test are

  • Low levels of 1, 25 Dihydroxy-Vitamin D may imply poor exposure to sun’s rays or poor absorption of vitamin D supplements
  • Drugs prescribed to treat seizures can lower the calcitriol levels
  • Low reading of calcium levels in tests can indicate diseases related to the kidney
  • High levels may indicate

1.      Excess supplementation from Vitamin pills

2.      Excess parathyroid hormones

3.      Some forms of Lymphoma

4.      Sarcoidosis

Precautions for vitamin D

The 1,25 Dihydroxy-Vitamin D test is extremely important to monitor Vitamin D levels that help in detecting and determining various health issues.


  • Vitamin D supplements should be strictly avoided if any allergy for the nutrient is detected
  • Another reason to avoid the supplement is when blood tests reveal excess Vitamin D in the sample


  • Having low magnesium and consequently low calcium levels will lead to

    1.      Lesser Vitamin D absorption

    2.      Imbalance in the release of the parathyroid hormone


  • Taking excess Vitamin D supplement can lead to

    1.      Damage of renal functions

    2.      Calcification of bones

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