Immunoglobulin G, Monitoring of Primary Immunodeficiency Treatment Profile
CPT:
82784; 82787(x4)
Synonyms
- IgG Subclasses
- IgG1,2,3,4
- Intravenous Immunoglobulin Treatment Monitoring
- Primary Immunodeficiency Treatment Monitoring
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
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Information
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
Monitoring the treatment of patients with intravenous IgG infusions who exhibit primary immunodeficiency with recurrent infections
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 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.
Methodology
Immunologic
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:
IgG1 | IgG2 | IgG3 | IgG4 |
>480 | >256 | >32 | >32 |
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
Footnotes
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
LOINC® Map
| 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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