investigation
Last reviewed 01/2018
During an acute attack there are:
- elevated plasma levels of activated C1
- decreased levels of C2 and C4
In between attacks
- decreased levels of C4 (rarely levels may be normal between attacks)
- normal C1 and C3 levels
- antigenic and functional C1-inhibitor levels differentiate type 1 hereditary
angioedema from type 2
- in type 1 - both antigenic and functional C1-inhibitor levels are low
- in type 2 - antigenic C1-inhibitor levels are normal but functional C1-inhibitor activity is low (1)
Reference: