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Vitamin D binding protein (DBP) concentration, serum/plasma

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

This test measures the amount of vitamin D binding protein in your blood. It helps assess how well vitamin D is transported in your bloodstream.

Quick summary

["This test supports vitamin D metabolism and function monitoring."]

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

Key facts at a glance

LOINC
49453-4
Short code
VZV DNA # Mar NAA+probe
Synonyms
VZV DNA # Mar NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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

What Is Vitamin D Binding Protein?

Vitamin D binding protein (DBP), also called group-specific component (Gc-globulin), is a protein in your blood that binds to vitamin D and other fat-soluble vitamins. It helps transport these vitamins to where they’re needed in your body, such as bones and muscles. Levels of DBP can vary based on factors like genetics, age, and health conditions.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms of vitamin D deficiency (e.g., fatigue, bone pain) or if you’re being evaluated for conditions like hypophosphatemia, kidney disease, or certain genetic disorders affecting vitamin metabolism.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay or nephelometry method to measure DBP levels.

What Do Results Mean?

Results provide a quantitative measure of DBP concentration in your blood. While reference ranges can vary by lab, abnormal levels may indicate underlying health concerns that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

DBP Level

Frequently asked questions

How does vitamin D binding protein relate to my health?
DBP plays a key role in vitamin D transport. Low levels may suggest conditions like hypophosphatemia or kidney dysfunction, while high levels could be linked to genetic variants or certain medications. Your provider will interpret results in the context of your overall health and symptoms.
What causes changes in DBP levels?
Changes in DBP levels can result from genetic factors, kidney disease, liver disease, or certain medications. Age-related changes may also occur, as DBP production can fluctuate with aging.
Does diet affect DBP levels?
Dietary factors like vitamin D intake or protein-rich foods may indirectly influence DBP function, but direct dietary effects on DBP concentration are less well-documented. Your provider will consider lifestyle factors during test interpretation.
  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