IgG Synthesis Rate/Index, CSF
Use
The IgG Synthesis Rate/Index in cerebrospinal fluid (CSF) is used for the diagnosis and monitoring of multiple sclerosis and other inflammatory diseases affecting the central nervous system. It assesses intrathecal IgG production by comparing CSF and serum IgG and albumin concentrations, with calculations of the IgG index and synthesis rate reflecting CNS-specific IgG synthesis compared to blood–brain barrier permeability. Elevated values may support identification of inflammatory demyelinating processes such as multiple sclerosis. ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/overview/2762?utm_source=openai))
Special Instructions
Specimens must include both CSF and serum, ideally drawn within a narrow time window (same time or within 12 hours). The CSF should be crystalline clear; collection should minimize blood contamination. Submit CSF in a sterile screw-cap container and serum using proper tube (e.g., SST or red-top). ([pathregional.com](https://pathregional.com/test/igg-synthesis-rate-index-csf/?utm_source=openai))
Limitations
Results can be confounded by blood contamination or hemolysis in CSF, which can spuriously elevate IgG and albumin measurements. Also, increased index or synthesis rate may occur in other inflammatory or infectious CNS processes besides multiple sclerosis, such as neurosyphilis or acute inflammatory polyradiculoneuropathy. ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/overview/2762?utm_source=openai))
Methodology
Other
Biomarkers
LOINC Codes
- 14117-6
- 2464-6
- 1746-7
- 2470-3
- 14116-8
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Cerebrospinal Fluid
Volume
1–2 mL
Minimum Volume
1 mL
Container
Sterile screw-cap container
Collection Instructions
CSF must be crystalline clear; avoid red cells; collected in sterile screw-cap vial.
Storage Instructions
Refrigerated
Causes for Rejection
Hemolysis or presence of red blood cells