Overview
The Vitamin D 25-Hydroxy Test is a blood test that measures the concentration of 25-hydroxyVitamin D, the major circulating form of Vitamin D in the body. This test is considered the most reliable indicator of Vitamin D status because it reflects both dietary intake and the amount produced in the skin after sunlight exposure.
Vitamin D is vital for maintaining strong bones and teeth, ensuring calcium absorption, supporting muscle strength, and keeping the immune system healthy. A deficiency can cause rickets in children, brittle bones and osteoporosis in adults, and may also contribute to fatigue, muscle weakness, and mood changes. Conversely, very high levels, usually due to excessive supplementation, can cause toxicity and lead to kidney or heart problems.
Doctors may recommend the Vitamin D 25-Hydroxy Test in the following circumstances:
Bone pain and weakness that could signal poor calcium metabolism.
Frequent fractures or brittle bones, often related to osteoporosis or osteopenia.
Children showing signs of rickets or delayed growth.
Monitoring chronic conditions such as kidney disease, liver disorders, or autoimmune conditions.
Evaluating malabsorption disorders like celiac disease, Crohn’s disease, or bariatric surgery effects.
Routine screening in elderly adults, pregnant women, breastfeeding mothers, or people with minimal sunlight exposure.
Tracking supplementation therapy to make sure prescribed Vitamin D doses are safe and effective.
This test provides critical insights that help doctors diagnose and manage deficiency or excess early.
The test measures 25-hydroxyVitamin D (25(OH)D) levels in blood. Results are typically classified as:
Deficiency: Less than 20 ng/mL – associated with bone and muscle problems.
Insufficiency: 20–29 ng/mL – borderline levels that may still cause symptoms.
Sufficiency: 30–100 ng/mL – considered the optimal range for health.
Toxicity: Greater than 100 ng/mL – may indicate dangerous excess.
These results guide doctors in recommending diet, supplements, or lifestyle adjustments.
The Vitamin D 25-Hydroxy Test is quick and straightforward:
A blood sample is collected from a vein in the arm.
No fasting or special preparation is needed before the test.
The collection process takes only a few minutes, and results are generally ready within one to two days.
Risks are very low, though mild pain, slight redness, or bruising at the puncture site may occur.
Frequently Asked Questions
What is the Vitamin D test cost in Bangalore?
Who should undergo this test?
Can the test detect both deficiency and excess?
How often should the test be repeated?