Immunoglobulin G, Monitoring of Primary Immunodeficiency Treatment Profile

CPT: 82784; 82787(x4)
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Test Details


  • IgG Subclasses
  • IgG1,2,3,4
  • Intravenous Immunoglobulin Treatment Monitoring
  • Primary Immunodeficiency Treatment Monitoring

Test Includes

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


Monitoring the treatment of patients with intravenous IgG infusions who exhibit primary immunodeficiency with recurrent infections


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 non-specific light scatter these sample types may generate. The results obtained from measuring IgG subclasses should not be used in assessing atopy in allergic patients.



Reference Interval

Total IgG trough level: >800 mg/dL

Note: Maintaining trough levels of total IgG above 800 mg/dL is reported to prevent serious bacterial illness, enteroviral meningoencephalitis, and pneumonia, but target trough levels may vary with individual patient.1-3

Approximate targets for trough levels for IgG subclasses (mg/dL)4:









Additional Information

In the past decades, administration of exogenous pooled human immunoglobulin for intravenous use (IVIG) has become an important therapy in clinical practice. Maintaining higher trough levels (>800 mg/dL of total IgG) in order to protect patients from recurrent infections have been reported.1-3 Percentages of relative abundance of human IgG subclasses for total IgG are reported to be approximately 60% for IgG1, 32% for IgG2, 4% for IgG3, and 4% for IgG4.4

Specimen Requirements




3 mL

Minimum Volume

1.8 mL


Red-top tube or gel-barrier tube


Transfer serum to a plastic transport tube.

Storage Instructions


Stability Requirements



Room temperature

3 days


7 days


13 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Gross lipemia; hemolysis

Clinical Information

Special Instructions

State patient's age on the test request form.


1. Orange JS, Hossny EM, Weiler CR, et al. Use of Intravenous Immunoglobulin in Human Disease: A Review of Evidence of Members of the Primary Immunodeficiency Committee of the American Academy of Allergy, Asthma, and Immunology. J Allergy Clin Immunol 2006 Apr; 117:S525-553.16580469
2. Orange JS, Grossman WJ, Navickis RJ, Wilkes MM. Impact of Trough IgG on Pneumonia Incidence in Primary Immunodeficiency: A Meta-analysis of Clinical Studies. Clin Immunol 2010 Oct; 137(1):21-30.20675197
3. Bonagura VR, Marchlewski R, Cox A, Rosenthal DW. Biologic IgG Level in Primary Immunodeficiency Disease: The IgG Level That Protects Against Recurrent Infection. J Allergy Clin Immunol 2008 Jul; 122(1):210-212.18602574
4. Vidarsson G, Dekkers G, Rispens T. IgG Subclasses and Allotypes: from structure to effector functions. Front Immunol. 2014 Oct; 5:520.25368619


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
123225 IgG, Treatment Monitoring 123226 Immunoglobulin G, Qn, Serum mg/dL 2465-3
123225 IgG, Treatment Monitoring 123227 IgG, Subclass 1 mg/dL 2466-1
123225 IgG, Treatment Monitoring 123228 IgG, Subclass 2 mg/dL 2467-9
123225 IgG, Treatment Monitoring 123229 IgG, Subclass 3 mg/dL 2468-7
123225 IgG, Treatment Monitoring 123230 IgG, Subclass 4 mg/dL 2469-5

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