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Test Code IGG Immunoglobulin G (IgG)

Additional Codes

Epic: LAB71

Specimen Required

Specimen Type: Serum

Collection Container/Type

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 3 mL

Collection Instructions: Centrifuge and separate cells after clot formation and within 4 hours of collection. 

 

Specimen Minimum Volume

0.25 mL

Specimen Stability

Room temperature: 4 months

Refrigerated: 8 months

Frozen: 8 months

Clinical Significance

IgG is the major immunoglobulin in the blood and is produced in copious amounts during secondary immune responses.  IgG molecules bind to specific receptors on phagocytic cells, such as macrophages and polymorphonuclear leukocytes, thereby increasing the efficiency with which the phagocytic cells can ingest and destroy infecting microorganisms that have become coated with IgG antibodies in response to the infection.  IgG molecules are the only antibodies that can pass from mother to fetus.  The ability of IgG to cross the placenta provides a major line of defense against infection for the first weeks of an infant’s life.  Quantitation of IgG can be used to evaluate humoral immunity, establish diagnosis and monitor therapy in IgG myeloma, and evaluate patients, especially children and those with lymphoma, with propensity to infections.  Reduction of IgG, usually less than 300mg/dL, leads to susceptibility to infection due to encapsulated bacteria.  Elevated IgG levels can be polyclonal, oligoclonal, or monoclonal.
Elevated polyclonal IgG levels are associated with autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, and Sjogren’s syndrome), chronic liver disease, some parasitic diseases, chronic or recurrent infections, and intrauterine contraceptive devices.  Increased oligoclonal IgG levels are associated with malignancies, infections (especially in the elderly), some dysgammaglobulinemias, and autoimmune disorders.  Increased monoclonal IgG levels are associated with multiple myeloma (IgG type), lymphomas, and leukemia.

Reference Range

0 - 1 month: 391 - 1765 mg/dL

1 month - 1 year: 203 - 948 mg/dL

1 - 2 years: 475 - 1226 mg/dL

2 - 150 yers: 540 - 1822 mg/dL

Rejection Due To

nlabeled, mislabeled, wrong tube type, visually lipemic, QNS, exceeds specimen stability requirements.

Day(s) and Time(s) Performed

Daily

Report Available

Same day / 1 day

Method Name

Immunoturbidimetric

Limitations

Samples containing paraproteins (abnormal monoclonal antibodies) may incorrectly fall within the reference range. Samples with elevated total protein concentrations or suspected paraproteinemia can be screened with other methods such as electrophoresis.  Turbidity and particles in samples can interfere with the assay.  Therefore, particulate matter should be removed by centrifugation prior to running the assay.

LOINC

2465-3