25-hydroxy vitamin D
Vitamin D plays an important role in bone and muscle health, and is essential for calcium absorption. This vitamin is mainly produced by our bodies through exposure to sunlight. Vitamin D can also come from external sources, such as food or supplements.
| What is the purpose of this test? | This test is performed to determine vitamin D levels in the blood. There are several reasons to measure vitamin D:
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| How to prepare? | No preparation needed. |
| Reference values* |
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| Associated tests | Other tests related to bone health may be performed at the same time, including the following:
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| How is it done? | A blood sample is drawn, usually from a vein in the arm. |
| How long before I get the results? | Results are usually ready in a day. It may take longer to receive your results. |
What does an abnormal test result mean?
High values of vitamin D:
- Excessive consumption of vitamin D supplements
- Sarcoidosis
- Certain lymphomas
Low values of vitamin D:
- Insufficient vitamin D intake
- Intestinal malabsorption of vitamin D, caused by factors that include the following:
- The use of certain medications (phenytoin, corticosteroids)
- Cystic fibrosis
- Crohn's disease or ulcerative colitis
- Celiac disease
- Stomach surgery
- Kidney or liver disease
What you should know before going for this test
When you go in for a blood test or any other medical exam, it's always a good idea to bring a complete list of any prescriptions, over-the-counter medications, or natural health products you're taking. Unless otherwise advised, it's best to take your medications as usual on blood test days. If in doubt, don't hesitate to talk to your healthcare professional.
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.