IgG Index and Synthesis Rate
Use
The IgG Index and Synthesis Rate test is used to assess the immunoglobulin production in the central nervous system (CNS). It is particularly useful in diagnosing and monitoring conditions such as multiple sclerosis, where the integrity of the blood-brain barrier is compromised and immunoglobulin production may be altered. This test helps distinguish whether an elevated IgG is due to CNS disease or reflects a systemic immune response.
Special Instructions
Turnaround time for results is typically 3 to 5 days, measured from the specimen pickup date to the release of results. Specimens require specific handling and storage instructions to maintain stability, with both serum and CSF needing to be collected. Use a red-top or gel-barrier tube for serum and a sterile container for CSF.
Limitations
False-positive elevations in the IgG index may occur in conditions where the CNS lyphoreticular elements produce immunoglobulins, such as aseptic meningitis, lymphoma, neurosyphilis, Guillain-Barré syndrome, and cerebral lupus erythematosus. These conditions are not usually associated with an elevated IgG index linked to multiple sclerosis.
Methodology
Immunoassay
Biomarkers
LOINC Codes
- 2464-6
- 1746-7
- 2465-3
- 1751-7
- 2470-3
- 14117-6
- 14116-8
- 1756-6
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.5 mL
Minimum Volume
0.7 mL
Container
Red-top tube or gel-barrier tube
Storage Instructions
Room temperature
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 6 months |