Immunoglobulin G, Quantitative

CPT: 82784
Print Share

Synonyms

  • IgG, Serum
  • Quantitative IgG, Serum

Test Includes

Quantitation of IgG


Special Instructions

Indicate patient's age on the request form.


Expected Turnaround Time

Within 1 day


Related Documents


Specimen Requirements


Specimen

Serum


Volume

1 mL (adult), 0.4 mL (pediatric)


Container

Red-top tube or gel-barrier tube


Storage Instructions

Samples suspected of having macroglobulins or cryoglobulins should be drawn and held at 37°C. Samples suspected of containing cold agglutinins should not be refrigerated prior to serum separation from clot.


Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3


Causes for Rejection

Excessive lipemia


Test Details


Use

Evaluate humoral immunity; monitor therapy in IgG myeloma; evaluate patients, especially children and those with lymphoma, with propensity to infections


Limitations

If samples containing macroglobulins, cryoglobulins, or cold agglutinins are handled at incorrect temperatures, false low values may result.


Methodology

Immunoturbidimetric


Reference Interval

See table.

Age

Male (mg/dL)

Female (mg/dL)

0 to 10 d

496−1231

496−1231

11 d to 6 m

175−639

184−697

7 to 11 m

261−791

295−787

1 to 3 y

428−1028

451−1071

4 to 6 y

538−1216

583−1262

7 to 9 y

580−1302

630−1350

10 to 11 y

601−1351

646−1407

12 to 13 y

610−1367

692−1433

14 to 15 y

630−1392

717−1463

16 to 19 y

671−1456

719−1475

>19 y

603−1613

586−1602


Additional Information

Immunoglobulin G is the major antibody containing protein fraction of blood. With significant decreases in IgG level, on either a congenital or acquired basis, there is an increased susceptibility to infectious processes ordinarily dealt with by humoral antibody (ie, bacterial infection). Thus, patients with repeated infection should have their immunoglobulins, and specifically IgG, measured. Therapy with exogenous γ-globulins may be efficacious in such patients. Conversely, IgG levels will be increased in immunocompetent individuals responding to a wide variety of infections or inflammatory insults (indeed, this represents the basis of the serologic diagnosis of infectious diseases). IgG specific antibody can now be demonstrated for numerous organisms, and when coupled with IgM specific antibody, can give an accurate diagnosis of acute or chronic infection. Today, a major cause for a polyclonal increase in IgG is the acquired immunodeficiency syndrome. Monoclonal IgG can be demonstrated in many cases of multiple myeloma. 3 g/dL of monoclonal IgG is a major diagnostic criterion for myeloma. Oligoclonal IgG can be seen in multiple sclerosis and some chronic hepatitides.

A monoclonal gammopathy may be present when the total IgG value is in the normal range. While many of these patients do not have multiple myeloma, evaluation of these patients for evaluation of the gammopathy and the presence of Bence Jones protein in urine is important.


LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
001776 Immunoglobulin G, Qn, Serum 2465-3 001776 Immunoglobulin G, Qn, Serum mg/dL 2465-3

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