C1 Esterase Inhibitor Antigen, Serum
Use
This test is useful for diagnosing hereditary angioedema and for monitoring the levels of C1 esterase inhibitor in response to therapy. C1 esterase inhibitor deficiency leads to inappropriate activation of C1, causing the release of kinin-like peptides that increase vascular permeability, resulting in acute edema. The condition is inherited in an autosomal dominant manner and responds to therapy with attenuated androgens. Despite normal antigen levels, some cases require functional measurements due to presence of nonfunctional proteins.
Special Instructions
Fasting for 12 hours is preferred but not required prior to specimen collection.
Limitations
Nephelometric quantitation of proteins may be inaccurate in lipemic sera due to light scattering properties of the specimen. Turbidity and particles can lead to extraneous light scattering signals and result in variable specimen analysis.
FDA ApprovedNew York Approved
Methodology
Immunoassay (Nephelometry)
Biomarkers
LOINC Codes
- 4477-6
- 4477-6
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Red top (preferred) or serum gel tube
Collection Instructions
Immediately place the tube on wet ice after collection, centrifuge, aliquot serum into a plastic vial, and freeze within 30 minutes.
Patient Preparation
Fasting: 12 hours, preferred but not required.
Causes for Rejection
Gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 28 days |
| Frozen | 28 days |