C1 inhibitor deficiency

Last updated: Monday, 26, July, 2010
CausesAppropriate Tests


Hereditary angioedema


Complement components C3 and C4. C1 inhibitor - immunological assay should be requested initially.

Functional assay should be requested if immunological assays are negative and there is a high index of clinical suspicion.


  • SLE
  • Carcinoma, especially
    • Colorectal
  • Lymphoma (non-Hodgkin's)