Varicella-Zoster Virus IgG Index, Serum and Cerebrospinal Fluid, Calculated
This test compares the level of varicella-zoster virus (VZV) antibodies in your cerebrospinal fluid with the level in your blood to help determine whether the virus is active in your central nervous system.
["The VZV IgG index helps show whether antibody in the spinal fluid is being produced locally, which can support a diagnosis of nervous-system VZV infection."]
Key facts at a glance
- LOINC
- 96961-8
- Short code
- VZV IgG Index Ser+CSF-aCnc
- Synonyms
- VZV 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 test measures immunoglobulin G (IgG) antibodies against varicella-zoster virus in both a serum (blood) sample and a cerebrospinal fluid (CSF) sample. A calculated index compares the two results, adjusting for the usual passage of antibodies from blood into spinal fluid.
Why It May Be Ordered
Your clinician may order this when there are signs of inflammation in the brain or spinal cord, such as meningitis or encephalitis, and VZV is a suspected cause. It can also be used when shingles or chickenpox has occurred and nervous-system symptoms appear afterward.
How the Samples Are Collected
A blood sample is drawn from a vein, and a cerebrospinal fluid sample is collected by lumbar puncture (spinal tap). Both samples are needed because the index is a comparison between them.
How to Interpret Results
A high index suggests that antibody against VZV is being produced within the central nervous system rather than simply leaking from the blood. Results are interpreted alongside symptoms, imaging, and other spinal fluid tests; an index alone does not confirm or exclude infection. Your care team will explain what your specific result means.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The VZV IgG index supports the evaluation of central nervous system infection caused by varicella-zoster virus. Because antibody production can take time and may persist, results must be interpreted with the clinical picture and other laboratory findings; they are not a stand-alone diagnosis.
Short name
VZV IgG Index (Serum/CSF)
Frequently asked questions
Does this test hurt?
Can I eat or drink before the test?
What if my result is borderline or unclear?
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