IgG4, Immunoglobulin Subclasses, Serum
Use
The IgG4, Immunoglobulin Subclasses, Serum test is primarily used to support the diagnosis of IgG4-related disease. IgG4-related disease is a systemic inflammatory condition that can affect multiple organ systems, presenting with tumor-like swelling and infiltration by IgG4-positive plasma cells. Elevated serum concentrations of IgG4 are found in a significant number of patients diagnosed with this disease, which includes conditions like autoimmune pancreatitis, Mikulicz disease, sclerosing sialadenitis, and several others. Measuring serum IgG4 can be a crucial part of the diagnostic process, often in conjunction with tissue biopsy and clinical assessment.
Special Instructions
Not provided.
Limitations
While elevated levels of IgG4 in the serum can support a diagnosis of IgG4-related disease, they are not exclusively indicative of it. Increased IgG4 levels can also be associated with other conditions such as multicentric Castleman disease, allergic disorders, Churg-Strauss syndrome, and sarcoidosis. Additionally, undetected antigen excess is rare but possible, meaning results need to be considered alongside other clinical and laboratory findings to ensure accurate diagnosis and treatment.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
IgG4
Analyte
LOINC Codes
- 2469-5 - IgG4 Ser-mCnc
- 2469-5 - IgG4 Ser-mCnc
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
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 and gross lipemia will lead to rejection. Gross icterus is acceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |