Test Overview
Test Methodology

Nephelometry

Test Usage

Evaluation of blood-brain barrier integrity and detection of local CNS IgG synthesis.

Reference Range *

CSF Albumin: 5-34 mg/dL; CSF IgG: 0-4.5 mg/dL; Serum Albumin (Adult): 3.5 - 4.9 g/dL; Serum IgG (Adult): 620-1520 mg/dL; IGG INDEX: 17-29 years: 0.32-0.60, 30-39 years: 0.34-0.59, 40-49 years: 0.36-0.56, 50-59 years: 0.33-0.57, 60-150 years: 0.34-0.58.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Tuesday, Friday
Analytic Time

8 hours

Soft Order Code
GIN
MiChart Code
IgG Index, CSF
Synonyms
  • GI Index
  • GIN
  • GIN IgG
  • IgG Index
  • IgG Synthesis Rate
  • Index, IgG
  • Multiple Sclerosis (MS)
  • ALBS
  • IGG
  • ALCSF
  • IGCSF
  • ALBUMIN - SERUM
  • IMMUNOGLOBULIN G
  • IMMUNOGLOBULIN G-CSF
  • ALBUMIN-CSF
  • IGG INDEX RESULT
Laboratory
Chemical Pathology
Section
Immunopathology
Specimen Requirements
Collection Instructions

Both blood and CSF samples must be obtained on the same day. Collect blood in SST tube. Centrifuge and aliquot serum into a plastic vial. Refrigerate serum and CSF.

Alternate Specimen
Red top tube.
Yellow Top Tube
Normal Volume
1.0 mL serum AND 1.0 mL CSF
Minimum Volume
0.5 mL serum AND 0.5 mL CSF
Additional Information

IgG Index = (CSF/Serum IgG ratio)/(CSF/Serum Albumin ratio). IgG Index may be increased in 75% of patients with multiple sclerosis (MS), in 69% with lupus cerebritis, in 33% with CNS infection, in 6-12% of other inflammatory disease, and in 3% of people with no clinical evidence of neurological disease. Oligoclonal bands will be present in 81% of MS patients and in less than 10% of patients with lupus cerebritis.

Billing
CPT Code
82784 x2, 82040, 82042
Fee Code
20520, 22202, 21987 x2
LOINC
1746-7 (CSF ALB), 2464-6 (CSF IgG), 1751-7 (Ser ALB), 38488-3 (Ser IgG), 14117-6 (IgG Index)
Resources