Serum or plasma mass concentration of 25-hydroxyvitamin D (25(OH)D)
This test measures the amount of vitamin D in your blood, which helps your body use calcium and bone health. Low levels may indicate vitamin D deficiency.
["Vitamin D helps maintain strong bones and supports overall health; check your levels if you suspect deficiency."]
Key facts at a glance
- LOINC
- 49837-8
- Short code
- DMPE MFr Amn
- Synonyms
- DMPE MFr Amn
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test to check if you have enough vitamin D in your blood. Common reasons include suspected deficiency, monitoring treatment for conditions like osteoporosis or rickets, or assessing risk for bone-related diseases. It may also be part of a general health check or screening for conditions like multiple sclerosis or certain autoimmune disorders.
What to Expect Before the Test
No special preparation is needed for this blood test. You may be asked to fast for 8–12 hours before the draw, but always follow your provider’s instructions. Wear a comfortable shirt and bring any medications you’re currently taking.
How the Test Works
A small blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to measure the specific vitamin D compound in your blood. The test uses a sensitive method to detect and quantify the vitamin D levels accurately.
What the Results Mean
Results are reported as a mass concentration of 25-hydroxyvitamin D in the blood. Your provider will interpret the results in relation to your health status and any symptoms you may have. Very low levels may indicate deficiency, while higher levels may suggest over-supplementation or other conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin D deficiency is linked to weakened bones, muscle weakness, fatigue, and increased risk of certain diseases. Proper levels are essential for bone health, immune function, and overall well-being. Your provider may recommend adjustments to diet, sunlight exposure, or supplements if levels are low.
Short name
Vitamin D level
Frequently asked questions
What causes vitamin D levels to be low?
How long does it take to get results?
Can I take vitamin D supplements without checking my levels first?
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