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
Study patients with recurrent bacterial infections or allergy
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 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.
Custom 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.
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 |
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 |
|---|---|---|---|---|---|---|
| 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 |
| Order Code | 209601 | |||||
| Order Code Name | IgG, Subclasses(1-4) | |||||
| Order Loinc | 47289-4 | |||||
| Result Code | 001776 | |||||
| Result Code Name | Immunoglobulin G, Qn, Serum | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2465-3 | |||||
| Order Code | 209601 | |||||
| Order Code Name | IgG, Subclasses(1-4) | |||||
| Order Loinc | 47289-4 | |||||
| Result Code | 160507 | |||||
| Result Code Name | IgG, Subclass 1 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2466-1 | |||||
| Order Code | 209601 | |||||
| Order Code Name | IgG, Subclasses(1-4) | |||||
| Order Loinc | 47289-4 | |||||
| Result Code | 160515 | |||||
| Result Code Name | IgG, Subclass 2 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2467-9 | |||||
| Order Code | 209601 | |||||
| Order Code Name | IgG, Subclasses(1-4) | |||||
| Order Loinc | 47289-4 | |||||
| Result Code | 160523 | |||||
| Result Code Name | IgG, Subclass 3 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2468-7 | |||||
| Order Code | 209601 | |||||
| Order Code Name | IgG, Subclasses(1-4) | |||||
| Order Loinc | 47289-4 | |||||
| Result Code | 160531 | |||||
| Result Code Name | IgG, Subclass 4 | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2469-5 |