SERPINA1 (Serpin Family A Member 1): SERPINA1 is a measure that reflects the activity of a key protease inhibitor in the body, also known as alpha-1-antitrypsin. Primarily produced in the liver, it plays a vital role in protecting the lungs from neutrophil elastase. Deficiency in SERPINA1 can lead to alpha-1-antitrypsin deficiency, a genetic condition associated with lung diseases such as emphysema and COPD, as well as liver disorders. It is essential for maintaining the balance of proteolytic activity in lung tissues.