IGG SYNTHESIS RATE
- Code
- 000.0000
- Name
- IGG SYNTHESIS RATE
- Category
- None
- Department
- Send-Out
- Start Date
- Expiration Date
- Synonyms
- IgG Synthesis Index
- CPT Codes
- 82040, 82042, 82784 x 2
- Site
- SBMF
- Reference Test
- 23069
Specimen Information
- Type
Cerebrospinal fluid (CSF), AND Serum (Gold Top SST)
- Volume
Pref Vol:
1.0 mL CSF, AND
1.0 mL serum
Min Vol:
0.5 mL CSF, AND
0.5 mL serum- Transport Info
Refrigerated
- Fasting Required?
- False
- Patient Instructions
- Reference Range
Albumin, Serum: 3.5-5.2 g/dL
Albumin, CSF: 0.0-35.0 mg/dL
IgG, Serum: 694-1619 mg/dL
IgG, CSF: 0.0-5.4 mg/dL
IgG/Alb Ratio: < 0.28
IgG/Alb Index: 0.3-0.7
IgG Synthesis Rate: -9.9 to 3.3 mg/day- Methodology
Photometry and nephelometry
Clinical Significance
The permeability of the blood-CSF barrier to plasma protein is increased by high intracranial pressure due to brain tumor, intracerebral hemorrhage, traumatic injury or by inflammation due to bacterial or viral meningitis, encephalitis or poliomyelitis. Demonstration of increased intrathecal synthesis of immunoglobulins, particularly IgG, has great importance in the diagnosis of demyelinating diseases of the Central Nervous System (CNS) especially multiple sclerosis (MS). In MS, patchy deterioration of the myelin sheaths of axions I the CNS profoundly affects conduction of nerve impulses.A complicating factor in testing for intrathecal IgG is that an increase in CSF IgG concentration or in the CSF/serum IgG concentration ratio may occur either because of increased permeability of the blood-CSF barrier or increased local production of IgG or both. To identify intrathecal production specifically, correction for increased permeability by including measurements of albumin in both serum and CSF is suitable because albumin is neither synthesized nor metabolized intrathecally.