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Vitamin D Binding Protein (DBP) Index

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

This test measures the ratio of your vitamin D binding protein levels to a reference standard, helping assess how well your body may be transporting vitamin D.

Quick summary

["This index helps evaluate vitamin D metabolism and potential deficiencies."]

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

Key facts at a glance

LOINC
100341-7
Short code
RUBV IgG Index Ser+CSF-aCnc
Synonyms
RUBV IgG Index Ser+CSF-aCnc
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

What This Test Measures

The DBP index evaluates the functional capacity of vitamin D binding protein (DBP), a protein in your blood that transports vitamin D. By comparing your DBP levels to a standardized reference, this test provides insight into how effectively your body may be utilizing vitamin D.

Why It Matters

Vitamin D binding protein plays a key role in transporting vitamin D through your bloodstream. Changes in this index may reflect underlying issues with vitamin D metabolism, which can impact bone health, immune function, and overall well-being.

How the Test Works

This test uses a blood sample to measure DBP concentration relative to a calibrated standard. The result is expressed as an index, indicating whether your DBP levels are within expected ranges for transporting vitamin D.

Common Reasons for Testing

Your healthcare provider may order this test if you have symptoms or risk factors related to vitamin D deficiency, such as fatigue, bone pain, or conditions like osteoporosis or autoimmune disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance of this test includes identifying potential vitamin D transport dysfunctions, which may require additional evaluation for underlying metabolic or genetic factors affecting vitamin D metabolism.

Short name

DBP Index

Frequently asked questions

What does a high or low DBP index mean?
A high DBP index may suggest increased DBP levels, potentially indicating overproduction or genetic variations in DBP. A low index could imply reduced DBP activity, though further testing would be needed to determine the cause.
Does this test replace standard vitamin D blood tests?
No, this index is a supplementary tool. Standard vitamin D tests (like 25-hydroxy vitamin D) are typically used first to assess overall vitamin D levels.
How often should I get this test?
Your provider will determine frequency based on your health status, symptoms, or risk factors. Routine testing isn’t standard unless recommended for specific conditions.
  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