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Distance: 25 KM
Actual Price: $22.00
Price: $22.00

Vitamin D 25 Hydroxy

Also known as

Ergocalciferol (Vitamin D2), Cholecalciferol (Vitamin D3), Calcidiol (25-hydroxyvitamin D), Calcifediol (25-hydroxy-vitamin D), Calcitriol (1.25 dihydroxy-vitamin D)

This test is ordered by the doctor to identify if the patient has vitamin D deficiency, if the patient is receiving Vitamin D supplementation or if the given supplementation is adequate or not.
This test is ordered as a follow-up to abnormal calcium, phosphorus, and/or parathyroid hormone levels. It is also ordered when the doctor thinks the patient has a bone disease or bone weakness due to certain symptoms and when the patient is at a high risk of or has vitamin D deficiency. The test is also given before starting the treatment for osteoporosis, a condition in which bones become porous. This test is ordered periodically in this case to monitor the treatment of vitamin D deficiency.
This is a blood test. A sample of blood is drawn from a vein in the arm.
There is no preparation needed for the test.
Vitamin D refers to a family of compounds that play a pivotal role in the proper growth and formation of bones and teeth. This test is used to measure the level of Vitamin D in the blood. Two forms of Vitamin D can be measured in the blood, 25 hydroxyvitamin D and 1.25-dihydroxyvitamin D. The former is the primary form that is found in the blood and is a relatively inactive precursor to the active form of vitamin D: 1.25 dihydroxy vitamin D. Since 25 hydroxyvitamin D has a long half-life and is present in higher concentrations in the blood, it is commonly measured to assess and monitor the status of vitamin D in the patient. Vitamin D is sourced from endogenous and exogenous sources. Endogenous sources are produced in the skin in response to exposure to sunlight, and exogenous sources are ingested in food and supplements. The role of Vitamin D is to help regulate the levels of calcium, phosphorus, and magnesium in the blood. Vitamin D is essential for the growth and health of bones. In the absence of vitamin D, bones tend to be malformed, soft, and unable to repair themselves normally. These circumstances lead to a disease known as rickets in children and osteomalacia in adults. Vitamin D has also been shown to play a role in the differentiation and growth of tissues and aids in regulating the immune system. These functions may implicate Vitamin D in varying conditions/diseases like cancer and autoimmunity. Patients at higher risk of vitamin D deficiency include the elderly, the obese, people with poor sun exposure, people who have dark skin, and those who are on certain types of medication for a long.
The test is used in multiple ways:
  • To identify if the patient has a bone weakness, bone malformation, or abnormal metabolism of calcium (as reflected by abnormal calcium, phosphorus, PTH). These conditions occur as a result of a deficiency or excess of vitamin D
  • To aid in the diagnosis of and monitoring problems with parathyroid gland functioning since PTH is essential for vitamin D activation
  • To screen people who are at high risk of deficiency, as recommended by the National Osteoporosis Foundation, the Institute of Medicine, and the Endocrine Society
  • To aid in monitoring the health status of individuals with diseases that hinder fat absorption, such as cystic fibrosis and Crohn's disease. This is because vitamin D is fat-soluble and is absorbed from the intestines like fats
  • Used to monitor people who have had gastric bypass surgery and may not be able to absorb enough vitamin D
  • Helps in determining how effective the treatment is when vitamin D, calcium, phosphorus, and/or magnesium supplementation is prescribed
The test for 25-hydroxyvitamin D is ordered when:
  • Calcium is low
  • The patient has symptoms of Vitamin D deficiency bone malformation, bone weakness, softness, or fracture
  • When the patient is at a known risk of Vitamin D deficiency, such as people who are homebound, older adults, people with limited sun exposure, people who have undergone gastric bypass surgery
  • People with fat malabsorption
The test for 1.25 hydroxyvitamin D is ordered when:
  • The patient has kidney disease; abnormalities of enzymes that convert 25-hydroxyvitamin D into an active form
Low levels of 25-hydroxyvitamin D imply that the patient is not getting enough sun exposure, dietary vitamin D, or there is an issue in absorption. Sometimes drugs used to treat seizures lead to interference in the production of 25-hydroxyvitamin D in the liver. Sometimes Vitamin Deficiency may increase the risk of some cancers, CVD, and immune diseases. Higher levels of the vitamin reflect an excess from supplements. Low levels of 1.25 dihydroxyvitamin are seen because of kidney diseases. Lower levels occur due to excess parathyroid hormone or in diseases like sarcoidosis and some lymphomas.
Related Tests

Calcium, Phosphorus, Magnesium, Parathyroid Hormone (PTH), Bone Markers, Trace Minerals