C1 Esterase Inhibitor, Functional

Test Code
C1EF


Preferred Specimen
1 mL frozen serum collected in a red-top tube (no gel)


Minimum Volume
0.2 mL


Instructions
Freeze serum within 1 hour of time drawn.
Do not use gel barrier tubes. Do not submit the sample in a glass tube. Do not thaw.


Transport Temperature
Frozen


Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Grossly lipemic • Serum separator tube (SST) • Received thawed


Methodology
Enzyme Immunoassay (EIA)

Setup Schedule
Sets up 3 days a week.


Clinical Significance
C1 esterase is decreased in angioedema. The inherited form is usually diagnosed in the first two decades of life. The acquired form affects primarily adults with autoimmune or lymphoproliferative disorders. Approximately 15% of patients with hereditary angioedema have a normal concentration of the protein but it is dysfunctional.




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.