Immunoglobulin G Index
Also known as: CSF IgG Index, CSF IgG:CSF Albumin Ratio, CSF IgG:CSF Total Protein Ratio, IgG Index, CSF, IgG Ratios and IgG Index, CSF
Use
Detect and measure the level of IgG production by the central nervous system; has been applied to the diagnosis of multiple sclerosis along with CSF IgG synthesis rate and CSF immunoglobulin “oligoclonal” bands
Special Instructions
The third tube of a routinely obtained three-tube set of cerebrospinal fluid (CSF) should be used for these studies.
Limitations
False-positive results may occur in conditions where lymphoreticular elements of the CNS produce immunoglobulins, such as aseptic meningitis, lymphoma, neurosyphilis, Guillain-Barré syndrome, and cerebral lupus erythematosus. While CSF IgG index is sensitive, it is not uniformly specific. Sensitivity levels can reach 80-90%, but specificity may be lower, requiring clinical judgment for interpretation. An increased IgG index without correlating oligoclonal bands may not provide specific value independent of other diagnostic indicators.
Methodology
Other
Biomarkers
LOINC Codes
- 2464-6
- 1746-7
- 2465-3
- 1751-7
- 2470-3
- 14117-6
Result Turnaround Time
3-6 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
Store at room temperature.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 6 weeks |
Other tests from different labs that may be relevant