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Test Code C1ESTIN C1 Esterase, Inhibitor Protein, Serum

Additional Codes

Sunrise Clinical Manager (SCM) Orderable:  

C1 Esterase Inhibitor Total, Serum

AllScripts (AEHR) Orderable: 

C1 Esterase Inhibitor Total, Serum

Performing Laboratory

Quest Diagnostics' Nichols Institute, Inc. - Chantilly



Specimen Requirements

Container/Tube:  Gold-top tube(s)

Specimen:  1 mL of serum (0.5 mL min)

Transport Temperature:  Refrigerated serum


Stability: 8 Days refrigerated

                1 Year Frozen

Reference Values

21-39 mg/dL



Fifteen percent of patient with the inherited form of the disease will test within range.

Test Classification and CPT Coding



LOINC code: 4477-6

Day(s) and Time(s) Performed

Monday through Saturday


TAT: 2 Days

Useful For

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

Computer Interface Code

PDM # 5900345