Vitamin D3 (1,25-OH D3)
Vitamin D3 (colecalciferol) is a type of vitamin D, a hormone-like precursor. It derived from 7-dehydrocholesterol which is produced by the skin, affected by UV-B radiation from sunlight.
Vitamin D plays an important role in many physiological processes, it is essential for bone formation and bone metabolism, it regulates calcium metabolism, and affects the functioning of the immune system. Through its effect on cellular metabolism, vitamin D3 supports the prevention of certain cancers.
Optimal levels of vitamin D cannot be provided from food, but by spending some time in sunlight. Necessary UV-B radiation can be provided between March and October with 15 minutes of direct sunlight reaching the face and exposed arms. Winter, early spring, and late autumn sun exposure is not enough to produce the right amount of vitamin D3, during this period it is recommended to supplement vitamin D with dietary supplements. The UV-A radiation in the solarium is not suitable for the formation of vitamin D3.
What does the test show?
The active vitamin D3 (1.25 OH D3, calcitriol), produced in the kidneys, regulates calcium metabolism, which provides information about the absorption of calcium and phosphorus in the body. This also indirectly refers to the body’s supply of vitamin D.
In what cases is it recommended to do the test?
The test is recommended primarily in case of suspicion of vitamin D deficiency. The following cases can cause vitamin D deficiency in the body:
- one-sided or decreased nutrition
- liver disease
- absorption disorders
- renal insufficiency
- taking antiepileptic drugs
In case of the above factors, the following symptoms may indicate a vitamin D deficiency:
- recurrent infections due to the weakness of the immune system
- fatigue, exhaustion
- slowed metabolism
- depression
- frequent bone fractures (osteomalacia, the softening of the bones)
- muscle, bone and joint pain
- muscle cramp
What kind of sample is needed for the test?
A blood sample, taken from a vein, is needed to perform the test.
What could the result indicate?
A value below the normal range indicates a lack of vitamin D3, as well as an inadequate calcium metabolism in the body. Calcium deficiency, caused by the lack of vitamin D, leads to bone loss, in severe cases, the structure of the bones change. It may also contribute to certain autoimmune diseases. The following diseases may cause lower values: osteoporosis, chronic renal insufficiency, nephrotic syndrome, hyperthyroidism, rachitis, tumor-induced osteomalacia, hypercalcemia not caused by parathyroid hyperfunction.
If the test shows a higher value than the normal range, there is D-hypervitaminosis, which also indicates high levels of calcium in the blood. It can also cause nausea, dehydration and constipation. Very rarely, in case of significant overdose, vitamin D poisoning may also occur. The following conditions or diseases may also cause elevated values: pregnancy, sarcoidosis, TB, lymphoma, tumor calcinosis, hypothyroidism, hyperparathyroidism, vitamin D treatment.
What to do after the test?
The result does not constitute a diagnosis in itself, therefore always consult your doctor or the specialist who ordered the examination to set the diagnosis and determine the necessary treatment.
