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HelpTest Code C1IHN C1 Esterase Inhibitor, Protein
Specimen Required
Specimen Type: Serum
Collection Container/Type
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Specimen Minimum Volume
0.5 mL
Specimen Stability
Room temperature: 7 days
Refrigerated: 8 days
Frozen: 1 year
Reference Range
21-39 mg/dL
Day(s) and Time(s) Performed
Mon-Sat p.m.
Report Available
Next day
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.
Method Name
Nephelometry
CPT Code(s)
86160
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153