Skip to content

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 is important for bone health and other bodily functions.

Quick summary

["Vitamin D helps maintain strong bones and supports immune function."]

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

Key facts at a glance

LOINC
22415-4
Short code
MuV IgG Ser Ql
Synonyms
MuV 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 healthcare provider may order this test if you have symptoms like muscle weakness, bone pain, or if you’re at 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 usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort afterward.

What Are Possible Results?

Results will show your vitamin D level in blood. Your provider will compare it to standard ranges to determine if you have sufficient, insufficient, or very low levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin D level

Frequently asked questions

What causes vitamin D deficiency?
Vitamin D deficiency can result from limited sun exposure, poor diet (low intake of fatty fish, fortified foods), certain medical conditions (like malabsorption), or taking certain medications that interfere with its absorption.
How long does it take to correct vitamin D levels?
Correcting vitamin D levels depends on the severity of deficiency. Supplements or sunlight exposure may help, but your provider will guide you on the best approach and monitor progress over time.
Can vitamin D levels fluctuate naturally?
Yes, vitamin D levels can change with seasons, sun exposure, and lifestyle. Regular testing helps track trends and ensure you’re maintaining healthy levels.
  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