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Serum or plasma concentration of vitamin D (25-hydroxyvitamin D)

Published: August 9, 2026Updated: August 16, 2026

This test measures your body’s level of vitamin D, an important nutrient that helps your bones stay strong and supports overall health.

Quick summary

["Vitamin D levels help assess your risk for deficiencies and related health issues like bone disorders or weakened immunity."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
110980-0
Short code
JCV IgM Msmt Ser
Synonyms
JCV IgM 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 It’s Done

Your doctor may order this test if you have symptoms of low vitamin D, such as fatigue, muscle pain, or frequent infections. It’s also used to monitor vitamin D levels in people who take supplements or have conditions that affect vitamin D absorption, like certain gastrointestinal disorders.

What to Expect

A blood sample is taken from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The sample is sent to a lab for testing.

What the Results Mean

Results help determine if your vitamin D levels are sufficient, insufficient, or deficient. Low levels may indicate poor vitamin D absorption, limited sun exposure, or other health conditions.

Common Causes of Low Vitamin D

Vitamin D deficiency can result from limited sun exposure, certain medications, malabsorption issues (like celiac disease), or liver/kidney problems. Dietary sources like fatty fish, fortified dairy, or supplements can help restore levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Vitamin D level

Frequently asked questions

How long does it take to get my vitamin D test results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
Can I eat or drink anything before my vitamin D blood test?
For most vitamin D tests, you can eat and drink normally. However, if your doctor specifies fasting requirements, follow their instructions to ensure accurate results.
What should I do if my vitamin D levels are low?
If your levels are low, your doctor may recommend dietary changes, increased sun exposure, or vitamin D supplements under medical supervision. They’ll guide you on the best approach for your situation.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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