Code of Federal Regulations Title 21. Food and Drugs § 21.866.5250 Complement C 2 inhibitor (inactivator) immunological test system

(a) Identification. A complement C₁ inhibitor (inactivator) immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the complement C₁ inhibitor (a plasma protein) in serum. Complement C₁ inhibitor occurs normally in plasma and blocks the action of the C₁ component of complement (a group of serum proteins which destroy infectious agents). Measurement of complement C₁ inhibitor aids in the diagnosis of hereditary angioneurotic edema (increased blood vessel permeability causing swelling of tissues) and a rare form of angioedema associated with lymphoma (lymph node cancer).

(b) Classification. Class II (performance standards).