Advanced Diagnostic Laboratories

C1 Esterase Inhibitor Autoantibody

Test Code

INHA

Description

C1-INH is a serine protease inhibitor that inactivates proteins of complement, kinin, coagulation, fibrinolytic and “contact phase” systems. Proteins of this family share an amino acid sequence homology that confers a similar three-dimensional structure to the C terminal part (Serpin domain) that inactivates the target protease. Anti-C1-INH autoantibodies bind epitopes around the reactive center and convert C1-INH into an inactive protease. The presence of autoantibodies to C1-INH is a hallmark of acquired C1-INH deficiency and recurrent symptoms of angioedema which involves the subcutaneous tissue (causing nonpruritic, non-inflammatory, long-lasting swelling with no urticaria), the gastrointestinal mucosa (vomiting, diarrhea, abdominal pain) and the upper respiratory tract (dysphagia, voice change, respiratory stridor up to asphyxia and death). Early diagnosis and monitoring of a patient's C1-INH autoantibody titer can allow for more rapid and effective treatment and improve the patient's prognosis.

Collect

Serum from a Red top tube is the only acceptable sample type. Draw blood into a serum collection tube. The collection tube should be completely filled with blood. Invert tube several times to initiate the clotting process. Keep the tube filled with blood at room temperature for 30-60 minutes to allow the blood to clot.
Ensure that the blood is centrifuged within 60 (± 5) minutes of collection

Patient Prep

Centrifuge the collection tube at 1600 (± 200) x g (rcf) at 4°C (± 2°C) for 15 (±1) minutes. Affix tube label to a polypropylene cryogenic storage tube. Immediately transfer the cell-free serum to the cryogenic tube on ice and immediately store the cryogenic tube at -60°C or below in an ultra-low freezer.

Preferred volume: 1.0 mL serum
Minimum volume: 0.25 mL serum

Pediatric Collection

Minimum volume: 0.25 mL serum

Unacceptable Conditions

Thawed samples or samples stored at room temperature prior to shipment.

Storage Transport Temp

Ship samples overnight in a well-insulated container on dry ice. We receive samples Monday - Friday. Avoid sending samples on the weekend and holidays to ensure that samples arrive frozen.

Stability

-60°C or below in an ultra-low freezer - up to 2 years

Performed

Monday – Friday

Methodology

ELISA

Turnaround Time

Up to 4 weeks

Department

Complement Lab

Synonyms

Angiodema (Autoantibody to C1-inhibitor);Complement (Autoantibody to C1-inhibitor);Hereditary Angiodema (Autoantibody to C1-inhibitor);ELISA (Autoantibody to C1-inhibitor);Acquired Angiodema (Autoantibody to C1-inhibitor);C1INH (Autoantibody to C1-inhibitor);CEIAP

Study Offerings

RUO
CAP/CLIA

Related Tests

Acquired Angiodema: C1-INH function (CEIF), C1-INH level (CEIQ), C1q level (C1Q), C4 level (C4)

Reference Interval

Human Male: 0 – 36.3% of Standard
Human Female: 0 – 36.3% of Standard

Interpretation

Positive results should be interpreted with other complement tests including, CI inhibitor function, and C1 inhibitor level as well as C4 level.