Serum or plasma concentration of vitamin D (25-hydroxyvitamin D)
This test measures the amount of vitamin D in your blood, which is important for bone health and other bodily functions.
["Vitamin D helps maintain strong bones and supports immune function."]
Key facts at a glance
- LOINC
- 40508-4
- Short code
- JCV IgM Titr Ser Nt
- Synonyms
- JCV IgM Titr Ser Nt
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- neut
- CPT
- 82784
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test to check if you have enough vitamin D, which can be important for preventing conditions like osteoporosis or rickets, especially if you have limited sun exposure, a diet low in vitamin D-rich foods, or certain medical conditions that affect vitamin D absorption.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. Wear comfortable clothing and bring any necessary identification.
What Happens During the Test?
A healthcare professional will insert a small needle into a vein in your arm to draw blood. The process is quick and typically causes only mild discomfort. The blood sample is then sent to a lab for analysis.
What Are the Possible Results?
Results will show the level of vitamin D in your blood. Low levels may indicate vitamin D deficiency, while higher levels could be due to over-supplementation or other factors. Your doctor will interpret the results in relation to your health status.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin D deficiency can lead to weakened bones, muscle weakness, fatigue, or increased risk of certain health conditions like osteoporosis or autoimmune diseases. Conversely, very high levels may cause symptoms like nausea, confusion, or kidney problems, though this is rare without medical intervention.
Short name
Vitamin D Level
Frequently asked questions
Why might my vitamin D level be checked if I don’t have obvious symptoms?
What if my vitamin D level is low?
Can vitamin D levels change quickly, or does it take time to adjust?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy