Serum Vitamin D (25-Hydroxyvitamin D) Concentration
This test measures the amount of vitamin D in your blood, which helps your body absorb calcium and maintain strong bones. Low levels may indicate deficiency, which can affect bone health and other body functions.
["Check your vitamin D levels if you suspect deficiency or have symptoms like fatigue or bone pain."]
Key facts at a glance
- LOINC
- 25514-1
- Short code
- RUBV IgG Ser Ql
- Synonyms
- RUBV IgG Ser Ql
- 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 doctor may order this test to check if you have enough vitamin D in your blood. Common reasons include suspected deficiency, monitoring vitamin D levels after treatment, or assessing risk factors like limited sun exposure, certain medical conditions, or dietary habits.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re nervous, let your healthcare provider know—they can help make it more comfortable.
What the Results Mean
Results show your vitamin D concentration in nanograms per milliliter (ng/mL). While reference ranges vary by lab, low levels may indicate deficiency, which can cause symptoms like fatigue, muscle weakness, or bone pain. High levels might suggest over-supplementation or other conditions.
Possible Causes of Abnormal Results
Low vitamin D levels can result from limited sun exposure, poor diet, certain medical conditions (like kidney or liver disease), or medications that interfere with vitamin D absorption. High levels may be due to overuse of supplements or rare genetic disorders.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin D deficiency is linked to weakened bones, increased risk of fractures, and potential complications like muscle weakness or autoimmune disorders. Regular monitoring helps manage conditions like osteoporosis or other deficiencies. Your doctor may recommend adjustments to diet, supplements, or lifestyle based on results.
Short name
Vitamin D Level
Frequently asked questions
What does a ‘low’ vitamin D level mean for me?
How long does it take to get results?
Can I eat or drink anything before the 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