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Test ID: SFIN Cerebrospinal Fluid (CSF) IgG Index, Serum and Spinal Fluid

Reporting Name

Cerebrospinal Fl, CSF, IgG Index

Useful For

Aids in the diagnosis of multiple sclerosis

Clinical Information

Elevation of IgG levels in the cerebrospinal fluid (CSF) of patients with inflammatory diseases of the central nervous system (multiple sclerosis [MS], neurosyphilis, acute inflammatory polyradiculoneuropathy, subacute sclerosing panencephalitis) is due to local central nervous system (CNS) synthesis of IgG.

 

The 2 most commonly used diagnostic laboratory tests for MS are CSF index and oligoclonal banding. The CSF index is the CSF IgG to CSF albumin ratio compared to the serum IgG to serum albumin ratio. The CSF index is, therefore, an indicator of the relative amount of CSF IgG compared to serum. Any increase in the index is a reflection of IgG production in the CNS. The IgG synthesis rate is a mathematical manipulation of the CSF index data and can also be used as a marker for CNS inflammatory diseases.

Interpretation

Cerebrospinal fluid (CSF) IgG index is positive (elevated) in approximately 80% of patients with multiple sclerosis (MS). Oligoclonal banding in CSF is also positive in approximately 80% of patients with MS. The use of CSF index plus oligoclonal banding has been reported to increase the sensitivity to over 90%.

 

The index is independent of the activity of the demyelinating process.

Profile Information

Test ID Reporting Name Available Separately Always Performed
SFINC IgG Index, CSF No Yes
SFINS IgG, S No Yes

Analytic Time

Same day/1 day

Day(s) and Time(s) Performed

Monday through Saturday; 2 p.m.

Clinical Reference

1. Tourtellotte WW, Walsh MJ, Baumhefner RW, et al: The current status of multiple sclerosis intra-blood-brain-barrier IgG synthesis. Ann NY Acad Sci 1984;436:52-67

2. Bloomer LC, Bray PF: Relative value of three laboratory methods in the diagnosis of multiple sclerosis. Clin Chem 1981;27:2011-2013

3. Hische EA, van der Helm HJ: Rate of synthesis of IgG within the blood-brain barrier and the IgG index compared in the diagnosis of multiple sclerosis. Clin Chem 1987;33:113-114

4. Swanson JW: Multiple Sclerosis: update in diagnosis and review of prognostic factors. Mayo Clin Proc 1989;64:577-586

5. Markowitz H, Kokmen E: Neurologic diseases and the cerebrospinal fluid immunoglobulin profile. Mayo Clin Proc 1983;58:273-274

Method Name

Nephelometry

Specimen Type

CSF
Serum


Specimen Required


Both serum and spinal fluid are required. Spinal fluid must be obtained within 1 week of serum draw.

 

Specimen Type: Serum

Container/Tube: Red top or serum gel

Specimen Volume: 1 mL

Collection Instructions: Label specimen as serum.

 

Specimen Type: Spinal fluid

Container/Tube: Sterile vial

Specimen Volume: 1 mL

Collection Instructions: Label specimen as spinal fluid.


Specimen Minimum Volume

Serum, Spinal Fluid: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Refrigerated (preferred) 14 days
  Ambient  14 days
  Frozen  14 days
Serum Refrigerated (preferred) 14 days
  Ambient  14 days
  Frozen  14 days

Reference Values

CSF index: 0.00-0.85

CSF IgG: 0.0-8.1 mg/dL

CSF albumin: 0.0-27.0 mg/dL

Serum IgG

0-4 months: 100-334 mg/dL

5-8 months: 164-588 mg/dL

9-14 months: 246-904 mg/dL

15-23 months: 313-1,170 mg/dL

2-3 years: 295-1,156 mg/dL

4-6 years: 386-1,470 mg/dL

7-9 years: 462-1,682 mg/dL

10-12 years: 503-1,719 mg/dL

13-15 years: 509-1,580 mg/dL

16-17 years: 487-1,327 mg/dL

≥18 years: 767-1,590 mg/dL

Serum albumin: 3,200-4,800 mg/dL

CSF IgG/albumin: 0.00-0.21

Serum IgG/albumin: 0.0-0.4

CSF IgG synthesis rate: 0-12 mg/24 hours

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82040

82042

82784 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SFIN Cerebrospinal Fl, CSF, IgG Index In Process

 

Result ID Test Result Name Result LOINC Value
INDEX IgG Index, CSF 14117-6
IGG_S IgG, S 2465-3
ALB_S Albumin, S 1751-7
IGG_C IgG, CSF 2464-6
ALB_C Albumin, CSF 1746-7
AIGAS IgG/Albumin, S 6782-7
AIGAC IgG/Albumin, CSF 2470-3
SRATE Synthesis Rate, CSF 14116-8
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Behavioral, mml-Epilepsy, mml-Movement-Disorders, mml-Demyelinating-Diseases, mml-Neuroimmunology, mml-Neuromuscular, mml-Autonomic, mml-Neuro-oncology, mml-Pediatric, mml-Pain, mml-Spinal-Cord, mml-Neuro-ophthalmology