C1 ESTERASE INHIBITOR, SERUM

C1 Esterase Inhibitor, Serum

What it is

The C1 Esterase Inhibitor, Serum test measures the level of C1 esterase inhibitor (C1-INH), a protein that regulates the complement system in the immune response. It plays an essential role in preventing excessive inflammation and swelling. Low or dysfunctional levels are linked to hereditary or acquired angioedema.

Uses

This test is primarily used to diagnose hereditary angioedema (HAE), evaluate unexplained recurrent swelling episodes, and differentiate between hereditary and acquired forms of C1-INH deficiency. It also helps in monitoring therapy effectiveness in patients undergoing treatment for angioedema.

Symptoms That May Lead to the Test

Doctors may order this test if a patient experiences unexplained and recurrent swelling of the face, lips, tongue, throat, or extremities, abdominal pain due to intestinal swelling, or airway obstruction episodes not related to allergic reactions.

Abnormal Results

Low C1-INH levels or function: Suggests hereditary angioedema (HAE) or acquired angioedema. Patients with these conditions are prone to life-threatening airway swelling.

Normal levels: Usually indicate that symptoms are not due to C1-INH deficiency. Other causes of swelling may need investigation.

Risks

This is a simple blood test with minimal risks. Some patients may experience mild pain, bruising, or bleeding at the puncture site, and rarely dizziness or infection.