Test Overview
Test Methodology

Nephelometry

Test Usage

During evaluation of a patient for possible immunoglobulin deficiency, quantification of IgG, IgA and IgM are usually performed. However, normal levels of these immunoglobulins will not rule out some forms of immunodeficiency. Quantifying the subclasses of IgG may help determine the immune status of a patient with normal total IgG. It is known that some subclasses preferentially react to particular antigens. IgG2 antibodies react to carbohydrate antigens and polysaccharides, including bacterial capsules. IgG4 antibodies react to allergens and parasitic antigens. The latter antibody may represent a non-IgE antibody which could sensitize basophils for release of histamine with production of allergic symptoms. When IgG2 or IgG4 deficiency accompanies IgA deficiency, the patients are particularly prone to suffer from infections. Patients with ataxia telangiectasia can also have deficiency of IgG subclasses. While not a primary screening test, quantification of IgG subclasses can be useful in patients with IgA deficiency, and in individuals with normal levels of IgG but an apparent poor response to pyogenic bacterial infections. The diagnosis is quite likely when IgG and/or IgA levels are low. Patients with these deficiencies usually respond well to gamma globulin replacement therapy. IgG3 has high antiviral activity.

Reference Range *

Updated on: 11/28/2017

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Tuesday, Friday
Analytic Time

8 hours

Soft Order Code
GSUB
MiChart Code
IgG 1, 2, 3, and 4
Synonyms
  • IgG1 Quantitation
  • IgG2 Quantitation
  • IgG3 Quantitation
  • IgG4 Quantitation
  • IGG SUBCLASSES
  • IGG1
  • IGG2
  • IGG3
  • IGG4
  • IGG SUBCLASS 1
  • IGG SUBCLASS 2
  • IGG SUBCLASS 3
  • IGG SUBCLASS 4
Laboratory
Chemical Pathology
Section
Immunopathology
Specimen Requirements
Collection Instructions

Collect specimen in SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate.

Alternate Specimen
Red top tube.
Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.3 mL serum
Billing
CPT Code
82787 x4
Fee Code
KA009 x4
LOINC
Z39-8
Resources