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Vitamin D (25-Hydroxy)

Also known as Calcidiol, Vit D (25-OH)
3391814 81% Off
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  1. No special preparation is required.

Understanding Vitamin D (25-Hydroxy)

What is Vitamin D (25-Hydroxy)?

The Vitamin D (25-Hydroxy) test measures the level of vitamin D in the body. Vitamin D is a fat-soluble essential nutrient that helps the body absorb calcium & phosphorus to maintain strong bones & teeth and to have a healthy immune system. Vitamin D levels are a valuable indicator of many bone-related problems, such as rickets, osteomalacia, and osteoporosis.

Vitamin D is vital to many bodily functions, including immune system regulation, maintenance of bone health, and cell growth. It is also a multifunctional hormone that regulates the levels of nutrients like calcium and phosphorus. Vitamin D can be obtained from healthy exposure to sunlight. Additionally, dietary sources such as fortified foods, green vegetables, mushrooms, egg yolks, fatty fish, and vitamin D supplements can help the body maintain healthy levels of this nutrient. 

As per an NCBI (National Center for Biotechnology Information) study, vitamin D deficiency is highly prevalent across all age groups in India. Insufficient vitamin D levels can increase susceptibility to fractures, weakened muscles, fatigue, compromised immune function, and a higher likelihood of chronic illnesses like diabetes. The Vitamin D (25-Hydroxy) test examination can aid in assessing whether your body has an inadequate supply (deficiency) or an excessive amount of vitamin D, often resulting from excessive supplement intake. If such circumstances arise, it may be necessary to discontinue vitamin D supplements and seek medical advice.

Usually, no special preparation is required for this test; you may consume a regular diet before taking the test. However, it is generally recommended to stop taking vitamin D supplements before the Vitamin D (25-Hydroxy) test, as these supplements may affect the accuracy of the test results. 

Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. The test results will help them determine your medical condition, make recommendations for lifestyle modifications such as diet and exercise, prescribe medication if required to manage your condition, and formulate your overall treatment plan. 

What is Vitamin D (25-Hydroxy) used for?

The Vitamin D (25-Hydroxy) test can be done:

  • To determine deficient, insufficient, or toxic vitamin D levels in the body.
  • For routine checkups in individuals at high risk of vitamin D deficiency. The risk of vitamin D deficiency increases with obesity, limited sun exposure, weight loss surgery, digestive disorders like Crohn’s disease, kidney or liver disease, and the use of certain medicines like phenytoin.
  • In individuals with vitamin D deficiency symptoms, such as bone deformities, immune system dysfunction, muscle cramps, and dental abnormalities.
  • To monitor the adequacy of treatment in patients who are receiving vitamin D supplements.
  • To diagnose/monitor problems with the functioning of the parathyroid gland since the parathyroid hormone (PTH) is essential for vitamin D metabolism.

What does Vitamin D (25-Hydroxy) measure?

The Vitamin D (25-Hydroxy) test measures the levels of vitamin D in the body. It is an essential nutrient that can be synthesized in the body upon healthy exposure to sunlight or absorbed from dietary sources. It majorly exists in two forms: Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol). Vitamin D2 is present in plants, such as yeast or mushrooms, and is available as a supplement in fortified foods, and vitamin D3 is found in foods like cheese, green vegetables, mushrooms, egg yolks, and fatty fish.

Both forms of vitamin D (D2 and D3) need to undergo some chemical changes before being available for use in the body. These chemical changes take place in the liver or kidneys. The liver converts vitamin D to 25-hydroxyvitamin D (25-OH vitamin D). The Vitamin D (25-Hydroxy) test measures the level of this 25-OH vitamin D as it is the primary form of vitamin D that circulates in the blood.

Interpreting Vitamin D (25-Hydroxy) results


A lower vitamin D level than the normal reference range indicates vitamin D deficiency, which can be because of less sun exposure, dietary lack, or decreased absorption from the intestine.

A higher vitamin D level than the normal reference range indicates vitamin D intoxication, usually due to excess vitamin supplementation.


The vitamin D range is measured as nanograms per milliliter (ng/mL) or nmol/L and can vary from lab to lab.


Reference range (ng/mL)










  • This test does not include a separate vitamin D2 and D3 level analysis.     
  • There can be seasonal variation in 25 (OH) vitamin D levels, with values being 40-50% lower in winter than in summer. It is also influenced by sunlight, latitude, skin pigmentation, sunscreen use, and hepatic function.
  • 25 (OH) vitamin D levels can vary with age.
  • 25 (OH) vitamin D level is increased during pregnancy.


Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Vitamin D (25-Hydroxy)

Frequently Asked Questions about Vitamin D (25-Hydroxy)

Q. What is the vitamin D test used for?

The vitamin D test is done to measure the amount of vitamin D in individuals with symptoms such as bone deformities, dysfunction of the immune system, muscle cramps, and dental abnormalities, and to monitor the adequacy of treatment in patients who are receiving vitamin D supplements.

Q. What are the signs and symptoms of low vitamin D levels?

Signs and symptoms of vitamin D deficiency may include fatigue, bone pain, depression, hair loss, muscle weakness, appetite loss, pale skin, and sleep disturbances.

Q. How much vitamin D is needed daily?

The recommended daily amount of vitamin D is 400 international units (IU) for children up to age 12 months, 600 IU for people aged 1 to 70 years, and 800 IU for people over 70 years. For adults with vitamin D levels below 30 ng/mL, the Endocrine Society guidelines recommend a daily intake of 1,500–2,000 IU to restore healthy vitamin D levels.

Q. What are the causes of vitamin D deficiency?

Vitamin D deficiency can develop when usual intakes are lower over time than recommended levels, exposure to sunlight is limited, the kidneys cannot convert 25(OH)D to its active form, or absorption of vitamin D from the digestive tract is inadequate. Low levels of vitamin D are also more common in people who have milk allergy or lactose intolerance and those who consume an ovo-vegetarian or vegan diet.

Q. What is the right time to get the vitamin D test done?

The vitamin D test can be done at any time of the day. However, you should stop taking vitamin D supplements before the test to get accurate results.

Q. Are there any risks associated with the vitamin D test?

No, usually, there are no risks associated with this test. The blood sample is withdrawn with the help of a needle, and the process is fairly fast and relatively painless. Very rarely, you may experience excessive pain, bleeding, hematoma (blood collection under the skin), bruising, or infection at the site of the needle prick. Consult the doctor if you experience any of these.

Q. Who should be tested for vitamin D?

Vitamin D 25 (OH) should be tested in individuals who are undergoing therapy to prevent or treat osteoporosis, patients having signs and symptoms of low calcium level (hypocalcemia) or high calcium level (hypercalcemia). It should also be done in patients with cystic fibrosis, Crohn’s disease, and with gastric bypass surgery, patients receiving vitamin D therapy who do not demonstrate clinical improvement. Along with that, these tests can be done in elderly people, especially those with minimal exposure to sunlight, children and adults with suspected rickets and osteomalacia, respectively, and infants who are exclusively breastfed.

Q. What are some of the common vitamin D benefits for the body?

Vitamin D plays an important role in many bodily functions, including immune system regulation, bone health maintenance, and cell growth. It is a fat-soluble essential nutrient that helps the body absorb calcium & phosphorus to maintain strong bones & teeth. Vitamin D levels are also a useful indicator of many bone-related problems, such as rickets, osteomalacia, and osteoporosis.

Q. What are some of the easily available vitamin D food sources for vegetarians?

Some of the easily available vitamin D sources for vegetarians include mushrooms, broccoli, carrots, apples, bananas, rice, whole wheat, dairy products like milk and cheese, and fortified cereals.

Q. What are the additional lab tests needed to be performed in case of abnormal vitamin D test results?

Additional tests that can help establish vitamin D deficiency include 24-hour urine calcium, parathyroid hormone total or bone alkaline phosphatase level, serum calcium, and serum phosphorus level.

Q. What are some of the common side effects of vitamin D overdose?

Side effects of vitamin D deficiency include hypercalcemia which in turn can lead to nausea, vomiting, muscle weakness, neuropsychiatric disturbances, pain, loss of appetite, dehydration, polyuria, excessive thirst, and kidney stones. In extreme cases, vitamin D toxicity causes renal failure, calcification of soft tissues throughout the body (including in coronary vessels and heart valves), cardiac arrhythmias, and even death.

Q. What is osteomalacia?

Osteomalacia is the softening of the bones due to demineralization (the loss of minerals) and, most notably, by the depletion of calcium from bone. It is a characteristic feature of vitamin D deficiency in adults. Osteomalacia can also be caused by poor dietary intake or poor absorption of calcium and other minerals needed to harden bones.

Q. What are the sources of vitamin D?

Vitamin D is derived from endogenous sources and exogenous sources. Endogenous sources are produced in our body when our skin is exposed to sunlight. In contrast, exogenous sources can only be derived from other sources, as they are not made in our bodies. Dietary sources of vitamin D include fish, eggs, fortified dairy products, and nutritional supplements.

Q. What is osteoporosis?

Osteoporosis is a condition of fragile bones with increased susceptibility to fracture. Vitamin D and calcium deficiency are some of the leading causes of osteoporosis. Other risk factors can be genetics, lack of exercise, personal history of fracture as an adult, cigarette smoking, excessive alcohol consumption, history of rheumatoid arthritis, low body weight, and family history of osteoporosis. Usually, osteoporosis does not manifest itself until bone fractures occur. X-rays and bone mineral density tests can help diagnose osteoporosis.

Q. Is there any correlation between the nutrients vitamin D and calcium?

Optimal vitamin D levels are necessary to increase the efficiency of calcium absorption. Without adequate vitamin D, the body absorbs only 10% to 15% of dietary calcium. When the vitamin D levels are adequate, the intestinal calcium absorption increases to 30% to 40%.
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Vitamin D (25-Hydroxy) test price for other cities

Price inBangaloreRs. 389
Price inNew DelhiRs. 339
Price inKolkataRs. 339
Price inHyderabadRs. 339
Price inMumbaiRs. 339
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