C1 Esterase Inhibitor, Protein

Test Code
C1 LEVEL(298)

Quest Code
298

CPT Codes
86160

Preferred Specimen
1 mL serum

Minimum Volume
0.5 mL

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 7 days
Refrigerated: 8 days
Frozen: 1 year

Methodology
Nephelometry

Setup Schedule
Mon-Sat

Report Available
1 to 2 Day(s)

Reference Range
21-39 mg/dL

Clinical Significance
The C1 esterase inhibitor protein is a normal constituent of serum which functions as a serine proteinase inhibitor of the serpin family. The C1 esterase inhibitor inhibits the complement proteases C1r and C1s, as well as the proteases Kallikrein, factor XIa, XIIa and plasmin of the blood clotting system. The concentration of C1 esterase inhibitor protein is reduced to 10-30% of normal in patients with angioedema secondary to C1 esterase inhibitor deficiency (85% of patients with hereditary angioedema (HAE)); in 15% of patients with HAE, the concentrations of the inhibitor protein is normal but function is markedly reduced.

Performing Laboratory
Quest Diagnostics Nichols Institute
27027 Tourney Road
Valencia, CA 91355-5386



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.