Specimen:

Serum

Collection Medium:

Minimum:

Preferred minimum: 1.0 ml serum
Pediatric minimum:  0.5 ml serum

Delivery Instructions:

Mix well and place on wet ice.  Keep on ice and deliver to
laboratory immediately.

Analytic Time:

1 week

Reference Range:

11 - 26 mg/dL

Comments:

Avoid hemolysis.

Separate red top required per complement assay ordered.

Overnight fasting specimen is preferred.

Test
Limitations:

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 X1a, X11a 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.

Methodology:

Fixed Rate Time Nephelometry

CPT Code:

83883

See also:
C1q Complement Component Level, Serum or Plasma

See Additional Information:
Specimens Requiring Immediate Delivery