Test Details
Methodology
Immunologic
Result 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.
Test Includes
Quantitation of IgG1, IgG2, IgG3, IgG4, total IgG
Use
Monitoring the treatment of patients with intravenous IgG infusions who exhibit primary immunodeficiency with recurrent infections
Special Instructions
State patient's age on the test request form.
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.
Footnotes
Custom 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
Specimen
Serum
Volume
3 mL
Minimum Volume
1.8 mL
Container
Red-top tube or gel-barrier tube
Collection Instructions
Transfer serum to a plastic transport tube.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 3 days |
Refrigerated | 7 days |
Frozen | 13 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
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 |
Storage Instructions
Refrigerate
Causes for Rejection
Gross lipemia; hemolysis
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 | |
| Order Code | 123225 | |||||
| Order Code Name | IgG, Treatment Monitoring | |||||
| Order Loinc | ||||||
| Result Code | 123226 | |||||
| Result Code Name | Immunoglobulin G, Qn, Serum | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2465-3 | |||||
| Order Code | 123225 | |||||
| Order Code Name | IgG, Treatment Monitoring | |||||
| Order Loinc | ||||||
| Result Code | 123227 | |||||
| Result Code Name | IgG, Subclass 1 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2466-1 | |||||
| Order Code | 123225 | |||||
| Order Code Name | IgG, Treatment Monitoring | |||||
| Order Loinc | ||||||
| Result Code | 123228 | |||||
| Result Code Name | IgG, Subclass 2 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2467-9 | |||||
| Order Code | 123225 | |||||
| Order Code Name | IgG, Treatment Monitoring | |||||
| Order Loinc | ||||||
| Result Code | 123229 | |||||
| Result Code Name | IgG, Subclass 3 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2468-7 | |||||
| Order Code | 123225 | |||||
| Order Code Name | IgG, Treatment Monitoring | |||||
| Order Loinc | ||||||
| Result Code | 123230 | |||||
| Result Code Name | IgG, Subclass 4 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2469-5 |