Chronic obstructive pulmonary disease (COPD) is the most prevalent clinical disorder. It is generally considered to be due to an imbalance between proteolytic enzymes and their inhibitors. Deficiency of alpha 1-antitrypsin (α1-AT) is a recognized risk factor for COPD and is characterized by the progressive obstruction of airways, which is not fully reversible. Alpha-1-antityrpsin deficiency is widely under-diagnosed in many populations with majority of the individuals remaining undetected due to the delay in the onset and variability of respiratory symptoms. In 1997, WHO stated that 2-3% of all alpha-1-antitrypsin deficient individuals were homozygous for PiZ and recommended screening for α1-AT deficiency in individuals with COPD, all adults and adolescents with asthma as well as neonates, children and adults with unexplained liver disease. © 2021 Elsevier B.V., All rights reserved.