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HelpTest Code CASF IgG/Albumin Ratio, Spinal Fluid
Reporting Name
IgG/Albumin Ratio, CSFUseful For
Assessment of cerebrospinal fluid (CSF) IgG/albumin ratio in the absence of a paired CSF and serum specimen
Specimen Type
CSFOrdering Guidance
The cerebrospinal fluid (CSF) index in which the CSF IgG/albumin ratio is compared to the serum IgG/albumin ratio aids in the diagnosis of individuals with multiple sclerosis. See SFIN / Cerebrospinal Fluid (CSF) IgG Index, Serum and Spinal Fluid.
Specimen Required
Collection Container/Tube: Sterile vial
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 14 days |
Reference Values
CSF IgG: 0.0-8.1 mg/dL
CSF albumin: 0.0-27.0 mg/dL
CSF IgG/albumin: 0.00-0.21
CPT Code Information
82042
82784
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CASF | IgG/Albumin Ratio, CSF | 2470-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| IGG_C | IgG, CSF | 2464-6 |
| ALB_C | Albumin, CSF | 1746-7 |
| AIGAC | IgG/Albumin, CSF | 2470-3 |
Clinical Information
Elevation of IgG levels in the cerebrospinal fluid (CSF) of patients with inflammatory diseases of the central nervous system (CNS) (multiple sclerosis [MS], neurosyphilis, acute inflammatory polyradiculoneuropathy, subacute sclerosing panencephalitis) is due to local 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, and 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 IgG index is positive (elevated) in approximately 80% of patients with multiple sclerosis.
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Method Name
Nephelometry