IgG Subclasses, Serum
Use
Measurement of the concentrations of IgG subclass proteins in serum is useful in evaluating patients with clinical signs and symptoms of humoral immunodeficiency or combined immunodeficiency (cellular and humoral). Diminished concentrations of one or more IgG subclass proteins may occur in conditions like hypogammaglobulinemia, common variable immunodeficiency, or may be selective. Most patients with IgG subclass 2 deficiency present with recurrent infections such as sinusitis and pulmonary infections, and children may exhibit deficient antibody responses to antigens. Isolated deficiencies of IgG subclass 3 or 4 occur rarely, and their clinical significance is not well understood.
Special Instructions
Fasting for 12 hours is preferred but not required. If not ordering electronically, complete and send the General Request form.
Limitations
Measurement of IgG subclass proteins is not a first-order test for immunodeficiency disease. It should be performed in conjunction with tests for total IgG, IgA, and IgM when assessing for immunodeficiency. Elevations in IgG4 concentrations are nonspecific and can occur in other conditions such as allergic disorders and sarcoidosis. Result interpretation should consider possible antigen excess and should be compared with clinical evidence and other laboratory tests.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 47289-4
- 2465-3
- 2466-1
- 2467-9
- 2468-7
- 2469-5
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
Not provided
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial.
Patient Preparation
Fasting: 12 hours, preferred but not required
Causes for Rejection
Gross hemolysis, gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |