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 overall well-being. Low levels may indicate deficiency, which can affect muscle function and immune health.
["Vitamin D levels help assess your risk for deficiency and support bone and immune health."]
Key facts at a glance
- LOINC
- 34952-2
- Short code
- RUBV IgG+IgM Pnl Ser
- Synonyms
- RUBV IgG+IgM Pnl 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 if you have symptoms like muscle weakness, frequent infections, or if you’re at higher risk for vitamin D deficiency (e.g., limited sun exposure, certain medical conditions, or dietary habits). It’s also used to monitor treatment for conditions like osteoporosis or rickets.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your test uses a specific timing protocol. Bring any medications you’re currently taking to your appointment.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. The process is quick and usually causes only mild discomfort. The blood sample is sent to a lab for analysis.
What Are Normal Results?
Results are typically reported in nanograms per milliliter (ng/mL) or picomoles per liter (pmol/L). Your provider will compare your results to your individual reference range, which may vary based on age, sex, and other factors.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low vitamin D levels may indicate deficiency, which can lead to weakened bones, muscle pain, fatigue, or increased susceptibility to infections. High levels may suggest over-supplementation or certain medical conditions. Your provider will interpret results in the context of your overall health and symptoms.
Short name
Vitamin D Level
Frequently asked questions
How long does it take to get results?
What causes vitamin D deficiency?
Can I take vitamin D supplements if my levels are low?
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