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

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

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, affecting bone health or other health conditions.

Quick summary

["Vitamin D levels help prevent deficiencies that can lead to bone problems or other health risks."]

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

Key facts at a glance

LOINC
45220-1
Short code
LCMV IgM Ser Ql
Synonyms
LCMV IgM 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 healthcare provider may order this test if you have symptoms like muscle weakness, bone pain, or if you’re at higher risk for vitamin D deficiency, such as not getting enough sunlight, having limited sun exposure, or having certain medical conditions.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, typically drawn from your arm. If you’re taking certain medications that affect vitamin D metabolism, let your provider know.

What the Results Mean

Results help determine if your vitamin D levels are sufficient, insufficient, or very low. Your provider will interpret the results in relation to your health and symptoms.

Common Reasons for Testing

This test is often used to screen for vitamin D deficiency, monitor bone health, or check for conditions like osteoporosis, rickets, or other metabolic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin D level

Frequently asked questions

What could cause abnormal results?
Low levels may be due to limited sun exposure, poor diet, certain medical conditions (e.g., liver or kidney disease), or medications that interfere with vitamin D absorption. High levels could indicate over-supplementation or rare conditions.
How long will it take to get results?
Results are usually available within 1–3 business days, depending on your lab. Follow-up may be needed if results are outside expected ranges.
Can I adjust my vitamin D intake based on these results?
Only work with your healthcare provider to determine safe adjustments. They’ll guide you on dietary changes, supplements, or further testing if needed.
  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