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Vitamin D (total) | Laboratory research

Known as: Vitamin D
SKU: 1145


Study material: Venous blood
Response time (working day): 1-2
The test is done on an empty stomach: Yes
Home call service: Yes
Country: Georgia

General Information

Vitamin D. are a group of fat-soluble secosteroids that are responsible for increasing intestinal absorption of calcium, magnesium, and phosphate and have many other biological effects. It has an important role in calcium homeostasis and metabolism.

Vitamin D or calciferol is synthesized from provitamins during exposure to sunlight. The most important vitamins are D - Vitamin D2 (ergocalciferol) და Vitamin D3 (cholecalciferol).

Vitamin D2 Is a plant-derived form of vitamin D (ergosterol or provitamin D2), Vitamin D3 It is even obtained from animal foods (especially fatty fish or fish oil), food additives, or synthesized in the skin from 7-dehydrocholesterol (provitamin D3) by exposure to ultraviolet rays. The rate at which vitamin D is produced depends largely on the duration and intensity of the radiation exposure. The use of sunscreen, even with SPF15, reduces the production of this vitamin by 99,9%. Excessive production of vitamin D in the skin is prevented by the photosensitive conversion of vitamin D to tachysterol or lumisterol.

Vitamin D2 and vitamin D3 do not have significant biological activity, so they need to be metabolized into hormonally active forms. Activation of vitamins takes place in two stages, first in the liver and then in the kidneys. Fat-soluble vitamin D is transported in the circulation - Specific alpha 1 globulin - a vitamin D transporter protein (VDBP - Vitamin D Binding Protein) - as a complex. In the liver, vitamin D undergoes its first hydroxylation to form 25-OH Vitamin D (Calcidiol), A metabolite with limited biological activity.

25-Hydroxy Vitamin D, With an extended half-life (2-3 weeks), is the main circulating reservoir and the best indicator of the general status of vitamin D.

When should we take the test?

  • Diagnosis of vitamin D deficiency;
  • Differential diagnostics of the causes of rickets and osteomalacia;
  • Monitoring of vitamin D replacement therapy;
  • Diagnosis of hypervitaminosis.

Possible interpretation of the results

D Vitamin levels increase:

In case of excessive exposure to ultraviolet radiation.

D Vitamin levels decrease:

  • Hypoparathyroidism;
  • Primary hyperparathyroidism;
  • Chronic renal failure;
  • Rocket;
  • Malnutrition, malabsorption;
  • Steatorrhea;
  • Biliary and portal cirrhosis;
  • Osteomalacia associated with taking anticonvulsants;
  • Renal osteodystrophy;
  • Cystic-fibrous osteitis;
  • Thyrotoxicosis;
  • Pancreatic insufficiency;
  • Celiac disease;
  • Inflammatory bowel disease, intestinal resection;
  • Alzheimer's disease.

Additional information

More than 25% of 95-OH D vitamin in serum is 25-OH Vitamin D3; Serum 25-OH vitamin D2 levels increase only in patients receiving vitamin D2-containing medications. It is therefore highly informative to determine 25-OH vitamin D3 in the blood.

The exact level of 25-OH vitamin D, which reflects the optimal reserve of vitamin D in the body, is unknown. Mild or moderate deficiency may be associated with osteoporosis or secondary hyperparathyroidism. Severe deficiency leads to insufficient mineralization of newly formed bone tissue (osteoid), resulting in the development of rickets in children and osteomalacia in adults. Because it develops during bone growth, rickets causes a characteristic deformation of the bone. Changes in laboratory tests for rickets include hypocalcemia, hypophosphatemia, an increase in alkaline phosphatase, and parathyroid hormone. Vitamin D deficiency in adults is associated with bone pain and an increased risk of fractures.

The effects of vitamin D deficiency on organs other than bone have not been fully investigated, but may include increased susceptibility to infections, muscle discomfort, insulin resistance, development of type I diabetes, high blood pressure, heart failure, depression, schizophrenia, schizophrenia, schizophrenia, Increased risk of developing preeclampsia and malignant tumors (colon, prostate, breast, ovaries, Arachnoid lymphoma

Vitamin 25-OH D-The reason for the non-optimal level may be:

  • Insufficient exposure to the sun;
  • Inadequate food intake;
  • Decreased absorption of vitamin D in the intestine (biliary cirrhosis, short bowel syndrome, exocrine insufficiency of the pancreas, Crohn's disease, cystic fibrosis, celiac disease);
  • Increased catabolism of vitamin D (treatment with barbiturates and anticonvulsants, primary hyperparathyroidism);
  • Increased loss of vitamin D (nephrotic syndrome, peritoneal dialysis);
  • Decreased hepatic 25-hydroxylase activity secondary to severe liver disease;

Vitamin D deficiency is common especially in adolescents, women and the elderly. Numerous studies have shown that more than 50% of the elderly, as well as a similar percentage of women undergoing treatment for osteoporosis, have inadequate levels of vitamin D in the body.

Compared to the widespread prevalence of vitamin D deficiency, hypervitaminosis D is rare and occurs only in the case of prolonged exposure to high doses of vitamin D. This condition is clinically characterized by anorexia, nausea, vomiting, diarrhea, hypotension, nephrolithiasis, heart problems. Laboratory test results show severe hypercalcemia and hyperphosphatemia, as well as low levels of parathyroid hormone.


How to prepare for the test?

  • Material is an important condition for ensuring the quality of laboratory blood tests On an empty stomach, In the morning (before 12:00).
  • You should exclude alcohol, smoking, eating, and limiting physical activity 12 hours before the study.
  • In the morning, on the day of taking blood for research, you can drink water.
  • Exclude medications; If the medication cannot be omitted, the laboratory should be notified.

Research material

Venous blood


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25-OH-vitamina D



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