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IgG

IgG, Immunoglobulin G, Serum, Immunoglobulin G (IgG), IGG

Test Codes

EPIC: LAB71

Department

Chemistry

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within 12 hours of collection. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged collection tube refrigerated (2-8°C or 36-46°F). (Minimum Serum: 0.5 mL)

Rejection Criteria

• Grossly lipemic specimens.
• Hemolyzed specimens.
• Plasma specimens.

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Room temperature is acceptable for a maximum of 12 hours. (Minimum Serum: 0.5 mL)

Storage

Specimen Stability for Testing:

Centrifuged SST tubes, Red-top tubes, and Microtainers^®
Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 5 days

Laboratory

Royal Oak Automated Chemistry Laboratory

Performed

Sunday – Saturday.
Results available within 24 hours of receipt in the Laboratory.

Reference Range

Test Methodology

Nephelometry.

Interpretation

Decreased levels of IgG are associated with selective hypo-IgG, protein losing enteropathies, pregnancy, and nephrotic syndrome.

Increased IgG levels are associated with infectious diseases (hepatitis, rubella, infectious mononucleosis), parasitic diseases, rheumatoid arthritis, systemic lupus erythematosus, polyclonal and monoclonal gammopathies, multiple myeloma, monocytic leukemia, and Hodgkin's disease.

Half Life in Blood: 21 days.

Clinical Utility

IgG levels can be used to evaluate humoral immunity and aids in the diagnosis of conditions associated with IgG excess or depression. IgG can cross the placenta. IgG antibodies are the most important and persistent antibodies of the secondary immune response.

CPT Codes

82784
LOINC: 2465-3

Contacts

Last Updated

5/28/2025