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

Published: August 9, 2026Updated: August 17, 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 body.

Quick summary

["Understanding your DBP levels can support vitamin D metabolism and related health evaluations."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
61542-7
Short code
Years vit D alone PhenX
Synonyms
Years vit D alone PhenX
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
30
Ref high
100
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
phenx
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), is a protein in your blood that transports vitamin D and other fat-soluble compounds. It plays a role in regulating vitamin D availability and its effects on cells.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms or conditions linked to vitamin D metabolism, such as chronic kidney disease, liver disease, or unexplained vitamin D deficiencies. It may also be part of broader evaluations for genetic disorders affecting protein function.

How Is the Test Performed?

A blood sample is drawn from a vein, typically in your arm. The blood is then processed to measure the concentration of DBP using a specialized laboratory technique.

What Do Results Mean?

Results provide insight into your body’s ability to transport and utilize vitamin D. Abnormal levels may indicate conditions affecting protein function or vitamin D metabolism, though they are not always directly tied to vitamin D deficiency symptoms alone.

Reference range

NCBI: Vitamin D 30-100 ng/mL (sufficient)N/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

DBP Level

Frequently asked questions

What could high or low DBP levels indicate?
High levels of DBP might suggest conditions like nephrotic syndrome or certain genetic disorders that increase protein production. Low levels could be associated with kidney disease or other conditions affecting protein breakdown, though they don’t always directly correlate with vitamin D deficiency.
How does this test relate to vitamin D levels?
DBP helps transport vitamin D in the blood, but its levels alone don’t replace direct vitamin D measurement (like 25-hydroxyvitamin D). Together, they provide a clearer picture of vitamin D status and metabolism.
Does this test require fasting?
No fasting is required for this test. However, your doctor may ask for additional bloodwork, such as vitamin D levels, to interpret results fully.
  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 17, 2026. · Read our editorial policy