IgG Synthesis Rate/Index, CSF

Casandra

Casandra Test Code QD65527Version 1 (DRAFT)

Performing Lab

Lab Quest DiagnosticsLab Test ID 7558CPT Codes 82040, 82042, 82784

IgG Synthesis Rate/Index, CSF

Clinical Use

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))

Test Details