Diagnosing HAE
How to Diagnose HAE

It is important to note that MOST cases of angioedema or swelling are NOT HAE or C1 Inhibitor Deficiency. Laboratory analysis of blood samples, or genetic samples, are required to establish an HAE diagnosis.

There are three specific blood tests used to confirm Hereditary Angioedema Type I or II.

1. C1-inhibitor quantitative (antigenic)
2. C1-inhibitor functional
3. C4

Types of Angioedema

Table of Angioedema Types Download a Comprehensive Table of Angioedema Types (pdf)

Type I HAE - 85% of patients
This is the most common form of the disease and is characterized by low quantitative levels of C1-inhibitor.

Type II HAE - 15% of patients
Patients who have normal or elevated levels of C1-inhibitor, but the protein does not function properly.

HAE with Normal C1 Inhibitor
This form of angioedema is yet to be fully understood. Scientists have identified mutations in the gene for human coagulation Factor XII as one of the causes for HAE with Normal C1 inhibitor.

There are, however, many patients with no Factor XII mutation that suffer from recurrent swellings typically found in HAE patients.

The HAEA is actively funding research to find a cause and, more importantly, an effective treatment for patients suffering from HAE with Normal C1-Inhibitor.