Immunoglobulin G, Subclasses (1-4)

CPT: 82784; 82787(x4)
Print Share

Synonyms

  • IgG Subclasses
  • IgG1,2,3,4

Test Includes

Quantitation of IgG1, IgG2, IgG3, IgG4, total IgG


Special Instructions

State patient's age on the test request form.


Expected Turnaround Time

3 - 5 days



Related Documents


Specimen Requirements


Specimen

Serum


Volume

3 mL


Minimum Volume

1.8 mL


Container

Red-top tube or gel-barrier tube


Collection

Transfer serum to a plastic transport tube.


Storage Instructions

Refrigerate


Stability Requirements

Temperature

Period

Room temperature

3 days

Refrigerated

7 days

Frozen

13 days

Freeze/thaw cycles

Stable x3


Causes for Rejection

Gross lipemia; hemolysis


Test Details


Use

Study patients with recurrent bacterial infections or allergy


Limitations

This procedure is not suitable for the measurement of samples containing rheumatoid factor, paraproteins, other circulating immune complexes (CICs), or for lipemic or hemolyzed samples due to the unpredictable degree of nonspecific light scatter these sample types may generate. The results obtained from measuring IgG subclasses should not be used in assessing atopy in allergic patients.


Methodology

Immunologic


Additional Information

There are four subtypes, of which IgG1 and IgG2 comprise 85% of the total. IgG1 and IgG3 fix complement best; IgG3 is hyperaggregable and effects serum viscosity disproportionately.

IgG antibody responses to certain antigens occur to a greater extent in one type of IgG subclass than another. Therefore, some patients with normal total IgG levels may have problems with pyogenic infections because they do not produce IgG2 or combinations of IgG2, IgG3, and/or IgG4. Some clinically significant IgG subclass deficiencies occur in patients who have IgA deficiency.

The four subclasses of IgG differ in the constant regions of their heavy chains. A patient may have a normal total IgG yet still have a significant decrease in one subclass. IgG1 deficiencies are associated with EBV infections, IgG2 with sinorespiratory infections and infections with encapsulated bacteria, IgG3 with sinusitis and otitis media, and IgG4 with allergies, ataxia telangiectasia, and sinorespiratory infections. See tables in individual subclass listings.


LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
209601 IgG, Subclasses(1-4) 47289-4 001776 Immunoglobulin G, Qn, Serum mg/dL 2465-3
209601 IgG, Subclasses(1-4) 47289-4 160507 IgG, Subclass 1 mg/dL 2466-1
209601 IgG, Subclasses(1-4) 47289-4 160515 IgG, Subclass 2 mg/dL 2467-9
209601 IgG, Subclasses(1-4) 47289-4 160523 IgG, Subclass 3 mg/dL 2468-7
209601 IgG, Subclasses(1-4) 47289-4 160531 IgG, Subclass 4 mg/dL 2469-5

For Providers

Please login to order a test

Order a Test

© 2021 Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.

CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2021, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf