Fasting for the test?You do not need to fast for this blood test. The results typically take about 48 hours.
Vitamin D - What is it?This blood test measures the amount of vitamin D in the blood. There are two forms of this vitamin, the active and non-active form. It is common to test the non-active form of vitamin D in the blood to determine a deficiency.
The blood value determination for vitamin D identifies whether there is a deficiency. Often, symptoms of fatigue or lethargy can be explained by a vitamin D deficiency. Many people in the Netherlands take supplements, as there is little sunshine. Vitamin D is a fat-soluble vitamin (like vitamins A, E, and K). A deficiency of this vitamin causes symptoms because vitamin D is necessary for the absorption of other substances (such as Calcium, Magnesium, and Phosphate). Therefore, a deficiency can also affect your bones, leading to conditions like rickets. Fortunately, this is rare in the Netherlands.
In our body, vitamin D3 (cholecalciferol) is the most important vitamin D molecule that is made in the skin and activated in the rest of the body (kidney and liver). This is the non-active form, and it is what we measure in the blood test. The active form, calcitriol, is mainly activated in the kidneys.
What do we determine?We determine the inactive form of vitamin D, also known as vitamin D3 or cholecalciferol, or in molecular terms, 25-hydroxy vitamin D.
It is important to maintain the inactive form (25-hydroxy vitamin D) between 50 and 150 nmol/L. However, for others with persistent symptoms, it is advisable to maintain a higher minimum value.
When to choose this test?Opt for this vitamin blood test when:
- You want to know if a vitamin-rich diet/lifestyle is effective
- You have been feeling tired for a while and think it may be due to a vitamin D deficiency
- You want to measure the effect of vitamin supplements or pills
- You want to detect problems with your parathyroid gland