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Vitamin D Binding Protein (DBP) or Group-Specific Component (GC) Serum Concentration

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

This test measures the level of a protein in your blood that helps transport vitamin D and other substances. It may also be called Group-Specific Component (GC).

Quick summary

["This test helps assess how your body processes certain vitamins and minerals."]

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

Key facts at a glance

LOINC
31894-9
Short code
MuV Ag Ser Ql
Synonyms
MuV Ag 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
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 Does This Test Measure?

The test measures the concentration of a protein called Group-Specific Component (GC), also known as Vitamin D Binding Protein. This protein binds to and transports various substances, including vitamin D, in the bloodstream. It can also be involved in immune system regulation.

Why Might You Need This Test?

Your healthcare provider may order this test if they suspect conditions affecting protein metabolism, vitamin D levels, or immune function. It can also be part of broader evaluations for genetic disorders or certain metabolic conditions.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is processed to separate serum (the liquid part after clotting) for testing. This test does not require fasting.

Common Reasons for Testing

Common reasons include evaluating hereditary conditions like GC deficiency, assessing vitamin D metabolism, or investigating symptoms related to protein disorders or immune system issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin D Binding Protein (DBP) or GC

Frequently asked questions

What Are the Possible Results and What Do They Mean?
Abnormal levels of Group-Specific Component (GC) may indicate genetic disorders, liver disease, or other metabolic conditions. Low levels could suggest hereditary deficiencies, while high levels might be associated with certain genetic disorders or liver problems. Consult your healthcare provider for interpretation.
How Often Should I Get This Test?
The frequency of this test depends on your medical condition and healthcare provider’s recommendations. If you have a known genetic predisposition or specific symptoms, your provider may schedule regular follow-ups.
What Should I Do If My Test Results Are Abnormal?
If your results are abnormal, your healthcare provider will discuss further steps, which may include additional tests, lifestyle changes, or treatment options tailored to your condition.
  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