Alpha-1-antitrypsin
A protein made by the liver that protects the lungs from an enzyme that would otherwise break down their delicate tissue. Its key use is to detect alpha-1-antitrypsin deficiency, an inherited condition where a low level leads to early emphysema and, in some, liver disease.
What it measures
Alpha-1-antitrypsin is a protein produced by the liver and released into the blood, where its job is to protect tissues — especially in the lungs — from an enzyme (neutrophil elastase) that would otherwise digest their elastic walls. Measuring its level is used mainly to detect alpha-1-antitrypsin deficiency, an inherited condition in which the liver makes a faulty version of the protein. Because the abnormal protein cannot leave the liver cells properly, the blood level is low (so the lungs are unprotected) and the protein also builds up inside the liver (which can damage it). The result is that people with the deficiency can develop emphysema — a form of chronic lung damage — often at a younger age than usual and especially if they smoke, as well as liver disease that can range from mild to cirrhosis. It is also an acute-phase protein, meaning the level rises with inflammation or infection, so a result is interpreted with that in mind. A low level prompts confirmatory genetic testing (the specific gene variants, such as the Z and S alleles).
What a high value can mean
- Inflammation or infection — it is an acute-phase protein, so the level rises with these; usually not significant in itself.
- A normal or high level makes a deficiency unlikely — reassuring when the deficiency is the question.
What a low value can mean
- Alpha-1-antitrypsin deficiency — the key finding; an inherited low level that leaves the lungs unprotected and can affect the liver.
- Reason to test the gene variants — a low level prompts confirmatory genetic (phenotype/genotype) testing.
- Severe liver disease — a failing liver may make less of it.
When to discuss with a doctor
Alpha-1-antitrypsin is worth checking in specific situations: emphysema or COPD developing at a younger age or in someone who has never smoked, unexplained chronic liver disease, or a family history of the deficiency. A low level is followed by confirmatory genetic testing to establish the diagnosis. Diagnosis matters because avoiding smoking (and other lung irritants) is the single most important step to protect the lungs, and both the lungs and liver can then be monitored and managed, with specific treatments available in some cases. Because the level rises with inflammation, a borderline result may be repeated when well. Mediora.AI can highlight a low alpha-1-antitrypsin alongside liver markers so the pattern is visible, but confirming and managing the deficiency belongs with your doctor and, usually, a specialist.