Serum Vitamin D (25-Hydroxyvitamin D) Level
This test measures the amount of vitamin D in your blood, which helps your body absorb calcium and maintain bone health. Low levels may indicate deficiency, while higher levels could signal overabsorption.
["Vitamin D levels affect bone health and may influence other health conditions."]
Key facts at a glance
- LOINC
- 110161-7
- Short code
- RUBV IgG Msmt Ser
- Synonyms
- RUBV IgG Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 healthcare provider may order this test to check for vitamin D deficiency, monitor vitamin D levels in people with certain medical conditions (like kidney disease or malabsorption), or evaluate symptoms such as muscle weakness, bone pain, or frequent infections.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your test involves a specific timing (e.g., 24-hour urine collection). Bring any medications you’re taking, as some may affect results.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. The process is quick and usually painless. You may feel a slight pinch, but most people tolerate it well. The blood sample will be sent to a lab for analysis.
What Are the Results?
Results are reported as a concentration of vitamin D in the blood (typically measured in nanograms per milliliter, ng/mL). Your provider will interpret the results in relation to your health status and symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin D deficiency is common and can lead to weakened bones (osteoporosis), muscle pain, fatigue, or increased risk of certain infections. High levels may indicate over-supplementation or other metabolic issues. Your provider will discuss results with you based on your medical history and symptoms.
Short name
Vitamin D Blood Test
Frequently asked questions
How long does it take to get my results?
Can I take vitamin D supplements before my test?
Does diet affect this test?
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