What is this test?
25-OH vitamin D is the best test for assessing the body's vitamin D status. Vitamin D is important for bone health, muscle strength and immunity; deficiency is common in people with little sun exposure and during the winter months. Because deficiency is easily corrected with supplements, regular testing is recommended.
When is it requested?
Vitamin D deficiency, osteoporosis
What does a high vitamin D result mean?
High vitamin D is almost always due to excess supplements; sun exposure alone does not lead to harmful levels. Very high levels can raise blood calcium.
- High-dose vitamin D drops, tablets or injections
- Long-term supplement use without follow-up testing
- Taking several vitamin D-containing products at once (multivitamins, fish oil, etc.)
- Incorrectly measured drop doses in children
What does a low vitamin D result mean?
Low 25-OH vitamin D means your vitamin D stores are insufficient; it is very common, especially in winter and in people who get little sun.
- Little sun exposure, indoor work, winter months
- Covering clothing or constant sunscreen use
- Darker skin and older age (the skin makes less vitamin D)
- Excess weight (vitamin D is stored in fat tissue)
- Breastfed babies who are not given vitamin D supplements
- Absorption problems such as celiac disease, kidney or liver disease
- Certain medicines (e.g., some epilepsy drugs, corticosteroids)
My result is outside the reference range. What should I do?
Don't take high-dose vitamin D without your doctor's advice. If treatment is started, rechecking the level after a few months is reasonable; calcium may be checked as well.
Reference ranges depend on the method, age and sex; always use the range printed on your report. This information is for general guidance only; consult your doctor for diagnosis and treatment.
Sample information
- Sample type: Serum
- Tube / container: Yellow-top tube
- Sample volume: 2 mL
Preparation
Serum (A 10-hour morning fast is required for sample collection. Protect the sample from light.)
Testing and results
- Method: CLIA
- Run schedule: Daily
- Turnaround time: 4 hours
Price and appointment
Add the test to your list to receive a price quote by e-mail, or call +90 850 640 07 30 / message us on WhatsApp (+90 537 301 22 14). You can have the test done at our branches or with our home blood collection service. Results can be viewed online with your Turkish ID number (or passport number for foreign nationals).