Serum amyloid A (SAA) is a protein produced by the liver in response to inflammation. It plays a role in the body's immune response and helps transport cholesterol and other lipids. SAA levels can increase significantly during infections, injuries, or chronic inflammatory conditions. High levels of SAA can be associated with various diseases, including rheumatoid arthritis, inflammatory bowel disease, and cardiovascular diseases. Monitoring SAA levels can help healthcare providers assess inflammation and track the effectiveness of treatments.