Vitamin D3 deficiency? 25-OH vitamin D level - Finger prick
This blood test measures the level of 25-hydroxyvitamin D [25(OH)D] in the blood via a finger prick. This is the most important marker for assessing the body’s vitamin D status.
What is vitamin D?
Vitamin D is a fat-soluble vitamin that plays an important role in the absorption of calcium and phosphorus and, therefore, in maintaining strong bones and teeth. In addition, vitamin D is involved in the normal functioning of the muscles and the immune system.
The body can produce vitamin D on its own in the skin when exposed to sunlight. We also get vitamin D from food, particularly from fatty fish, eggs, and foods fortified with vitamin D. If production and intake are insufficient, a deficiency can develop.
What does this test measure?
This test measures 25-OH-vitamin D in the blood. This is the most important circulating form of vitamin D and provides a good indication of the body’s vitamin D stores.
25-OH vitamin D should not be confused with 1,25-dihydroxyvitamin D [1,25-(OH)â‚‚D], the active form of vitamin D. This active form is primarily produced in the kidneys and is typically measured only for specific medical indications.
When might it be a good idea to get tested for vitamin D?
A vitamin D test may be considered in cases such as:
limited exposure to sunlight;
an increased risk of a vitamin D deficiency;
muscle weakness or unexplained muscle symptoms;
bone problems or an increased risk of osteoporosis;
conditions in which the absorption of nutrients in the intestine may be reduced;
use of certain medications that affect vitamin D metabolism;
Use of vitamin D supplements where monitoring blood levels is recommended.
People who spend little time outdoors, have dark skin, or cover most of their skin may be at increased risk of low vitamin D levels.
A low vitamin D level
A low 25-OH vitamin D level may indicate insufficient production or intake of vitamin D. Possible causes include:
insufficient exposure to sunlight;
Insufficient vitamin D from food or supplements;
reduced absorption in the intestines;
certain liver or kidney conditions;
use of certain medications.
Elevated vitamin D levels
Elevated 25-OH vitamin D levels are usually caused by excessive vitamin D intake from supplements. Vitamin D toxicity does not normally result from exposure to sunlight alone.
Very high vitamin D levels can lead to elevated calcium levels in the blood (hypercalcemia). This can cause symptoms such as nausea, fatigue, excessive thirst, and frequent urination, and in cases of severe or prolonged elevation, it can be harmful to the kidneys, among other organs.
What can you do if your vitamin D levels are low?
The appropriate course of action depends on the measured level, personal circumstances, and any symptoms or medical conditions. Increased exposure to daylight and sunlight, a diet rich in vitamin D, and/or supplementation can help improve vitamin D levels.
If your levels are significantly low, you have persistent symptoms, or you’re unsure about the correct dosage, it’s wise to discuss the results and any potential supplementation with a doctor.
Are you taking higher doses of vitamin D over an extended period? If so, a follow-up test may be helpful to determine whether your levels have risen sufficiently and are not becoming too high.
See also:Is your vitamin D level high enough?
