IgG, Serum

IgG, Quantitative, Serum

Alternate Test Name

IgG

Immunoglobulin IgG

Gamma globulin IgG

Epic Mnemonic
Sunquest Mnemonic

LAB71
IGG

Category

Chemistry

Methodology

Immunoturbidimetric assay

Test Performance Schedule

Sunday - Saturday

Result Availability

Within 24 hours

Container

Gold top (SST), Red top (serum), or Green top (lithium heparin) tube

Alt: EDTA / GREEN

Volume

Pref. Vol.: 1.0 mL serum or plasma
Min. Vol.: 0.5 mL serum or plasma

Collection Instructions

• Routine venipuncture

• Immediately after collection, gently invert tube 5-10 times

• Clot 30 minutes

• Promptly centrifuge

• If no gel barrier is present immediately transfer serum or plasma to a plastic tube and refrigerate

• Properly centrifuged gel barrier tube does not require transfer of serum or plasma to separate tube

Transportation Instructions

Refrigerated

Stability

• Room Temperature: 5 days
• Refrigerated: 5 days

CPT Codes

82784

Effective/Revised

03/24/2017

IgG molecules are composed of two light chains (kappa or lambda) and two gamma heavy chains. Approximately 80% of serum immunoglobulin is IgG; its main tasks are the defense against microorganisms, direct neutralization of toxins and induction of complement fixation. IgG is the only immunoglobulin that can cross the placental barrier and provide passive immune protection for the fetus and newborn. This maternal protection gradually declines until the infant's own immunological system starts to develop (at about six months of age). Near-adult levels in serum/plasma are reached at 18 months.

Polyclonal IgG increases in serum/plasma may be present in systemic lupus erythematosis, chronic liver diseases (infectious hepatitis and Laennec’s cirrhosis), infectious diseases and cystic fibrosis. Monoclonal IgG increases in IgG-myeloma.

Decreased synthesis of IgG is found in congenital and acquired immunodeficiency diseases and selective IgG subclass deficiencies, such as Bruton type agammaglobulinemia. Decreased IgG concentrations in serum and plasma are seen in protein-losing enteropathies, nephrotic syndrome and through the skin from burns. Increased IgG metabolism is found in Wiskott-Aldrich syndrome, myotonic dystrophy and with anti-immunoglobulin antibodies.