Definition of Serum amyloid A

Serum amyloid A: A superfamily of acute-phase proteins. The level of serum amyloid A (SAA) in the blood increases dramatically in response to tissue injury and inflammation. SAA also acts as a cytokine, influencing cell adhesion, migration, proliferation and aggregation.

Serum amyloid A is so-named because it is related to the A proteins of secondary amyloidosis. See also: Acute-phase protein.