Imperial Collage Healthcare

Complement C1 esterase inhibitor – antigenic


Test Background
C1 inhibitor deficiency causes hereditary angioedema (HAE). Patients present with acute deep tissue oedema, typically of the face, larynx or abdomen, which can be life threatening if respiratory obstruction occurs. 85 % of HAE patients have low antigenic C1 esterase inhibitor levels (type I HAE). The C4 level is low, especially during attacks. Request alongside C3 and C4 levels, plus C1 functional activity.


Clinical Indications
Recurrent angioedema, laryngeal oedema, or abdominal pain in the absence of urticaria Family history


Reference Range

0.22-0.38 g/L


Sample Required
RST (rust top) Separate and freeze immediately Transport frozen


Sample Volume
5-10 mL (1 mL serum)


Turnaround Time
21 days


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