The A-1-AT test assesses blood levels of Alpha-1 antitrypsin, an anti-inflammatory pulmonary protective protein produced in the liver that inhibits neutrophil elastase, preventing excessive enzymatic tissue breakdown in the lungs. A-1 AT deficiency is a genetic mutation leading to obstructive pulmonary diseases such as emphysema and liver problems. Monitoring its level helps healthcare providers slow disease progression and address AAT deficiency complications.