Complement C1 esterase inhibitor-13328

Test info

Complement C1 esterase inhibitor
C1 esterase inhibitor, antigen
C1 inactivator
C1 inhibitor
Esterase inhibitor
HANE assay
Hereditary angioneurotic edema test

C1 esterase inhibitor is decreased in hereditary angioneurotic edema; decrease may be functional or quantitative.


1.0 mL
0.5 mL

Immediately following collection, thoroughly mix sample by gently inverting 5 times

  1. Allow sample to clot for a minimum of 30 minutes
  2. Spin within 60 minutes of sample collection
  3. Transfer specimen to a Transfer vial/tube with cap - 12mL (LabCorp), labelled as serum
  1. Allow sample to clot
  2. Spin within 60 minutes of sample collection
  3. Transfer specimen to a Transfer vial/tube with cap - 12mL (LabCorp), labelled as serum

Ambient (preferred) - 14 days

Refrigerated - 14 days

Frozen - 14 days

Freeze/thaw cycles - stable x 3

  • Microbially-contaminated samples
  • Hemolysis
  • Gross lipemia that cannot be cleared by ultracentrifugation
  • Citrated plasma (heparinized plasma is acceptable)


LabCorp Burlington (004648): R-LC
Mo - Fr
2 - 4 days

Immunologic, quantitative

Clinical and Interpretive info


21 - 39 mg/dL


The more common form (85% of patients) of hereditary angioneurotic edema is due to an absolute decrease in the amount of C1 esterase inhibitor. A less common form (15% of patients) is due to a functional defect where quantitative levels may be normal. Both abnormalities must be tested for due to the potential life-threatening nature of the illness. In addition to decreased C1 esterase inhibitor in the serum of patients with hereditary angioneurotic edema, a unique polypeptide kinin is increased in plasma from C1 esterase inhibitor deficient patient during attacks of swelling. Danazol, a synthetic androgenic inhibitor of gonadotropin release, with little virilizing potential, decreases thenumber of clinical attacks in cases of hereditary angioneurotic edema. Patients with attacks of hereditary angioneurotic edema also have low total complement, C4 and C2. Consequently, measurement of serum C4 is an often used test. Hereditary angioneurotic edema is transmitted as an autosomal dominant trait. Heterozygotes also show decreased levels of C1 esterase inhibitor. During acute attacks of the disease, complement factors C4 and C2 can be markedly reduced, but C1 and C3 are normal. The initiating stimulus of clinical attacks is often unknown. Angioedema may also be an acquired illness. The acquired form includes nonhereditary C1 esterase deficiency; drug induced, allergic, and idiopathic forms, angioedemaassociated with autoimmune disease, especially with systemic lupus erythematosus and hypereosinophilia; angioedema occasionally associated with malignancy; and angioedema caused by physical stimuli. Angioedema has occasionally been known to precede development of lymphoproliferative disorders.


Result 4477-6