Vitamin D binding protein (DBP) concentration
This test measures the amount of vitamin D binding protein in your blood, which helps transport vitamin D and other hormones in your body.
["Assesses your body’s ability to transport vitamin D and related substances."]
Key facts at a glance
- LOINC
- 26890-4
- Short code
- CDV-IGM-CSF
- Synonyms
- CDV IgM Titr CSF IF
- Category
- chemistry
- Sample
- csf
- Container
- Sterile, leak-proof cryogenic vial or microcentrifuge tube; CSF collection tube (tube #3 or #4 recommended to minimize blood contamination)
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunofluorescence (IFA)
- CPT
- 82784
- SNOMED
- 36851000119109
- Specimen volume
- 0.5-1.0 mL of cerebrospinal fluid
- Stability
- Refrigerated (2-8°C): up to 48 hours; Frozen (-20°C or below): up to 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 200
- TAT
- 24–72 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 binds to vitamin D and other hormones like cortisol and thyroid hormones. It helps transport these substances efficiently throughout your body.
Why Might You Need This Test?
Doctors may order this test if you have symptoms related to vitamin D deficiency, kidney disease, or conditions affecting hormone regulation. It can also be part of broader evaluations for metabolic or endocrine disorders.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed using a specialized 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 vary by lab, abnormal levels may indicate underlying health concerns, such as kidney disease or genetic variations affecting protein function.
Reference range
Titer < 1:5 (Negative); Titer ≥ 1:5 (Positive) — interpretive values vary by reporting laboratoryN/A
Patient should be fasted for 12 hours prior to CSF collection under general anesthesia. Neurological examination should be performed prior to lumbar cisternal or lumbar puncture.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin D binding protein plays a role in maintaining hormone balance and vitamin D metabolism. Abnormal levels may suggest conditions like nephrotic syndrome (kidney disease), genetic disorders (e.g., GC deficiency), or other metabolic issues. It is often measured alongside vitamin D levels to assess overall vitamin D status and hormone transport efficiency.
Short name
DBP Level
Frequently asked questions
What causes abnormal vitamin D binding protein levels?
How often should I get this test?
Can lifestyle changes affect vitamin D binding protein levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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