Alpha-1 antitrypsin blood test

What is Alpha-1 Antitrypsin Blood Test?

Alpha-1 antitrypsin (or A1AT) is a protein found in human blood. It helps to protects the body from damage caused by its own enzymes. A1AT blood tests are used to measure the levels present in the blood. High or low levels can indicate certain conditions such as liver problems or absent alpha-1 antitrypsin deficiency (A1AD).

Purpose of Test

The test is ordered to determine if someone has a deficiency of alpha-1 antitrypsin. This deficiency can lead to liver damage and even liver failure. It is also used to diagnose some types of lung disease, including chronic obstructive pulmonary disease (COPD), emphysema, and asthma.


Most of the time, no preparation is needed before an A1AT blood test. Some labs may ask that you fast (not eat or drink) for eight hours before the test. It is best to check with your doctor or the laboratory for specific instructions.


To perform an A1AT blood test, a technician will draw blood from a vein in the arm using a needle. The sample is then sent to a lab for analysis and interpretation of the results. It usually takes a few days for the results to become available.


  • Normal A1AT protein levels range from 60-150 milligrams per deciliter (mg / dl).
  • Low levels of A1AT are associated with alpha-1 antitrypsin deficiency (A1AD). Low levels can indicate a hereditary condition or liver problem.
  • High levels of A1AT can indicate chronic inflammation, some infectious diseases, and certain medications.


The risks of an A1AT blood test are minimal. You may experience brief discomfort and minor bleeding at the puncture site. As with any blood test, there is the rare chance of an allergic reaction to the needle or an infection.

When to Get Tested

Your doctor may order an A1AT blood test if you have any of the following: family history of alpha-1 antitrypsin deficiency, liver disease, lung problems, or unexplained breathing difficulties. It is also ordered to monitor any existing conditions or as part of a routine physical examination.

Why to Get Tested

Alpha-1 antitrypsin blood testing is important as it can help diagnose and monitor liver and lung conditions. Early diagnosis and treatment can help prevent serious complications such as liver failure or emphysema. It is also helpful to know if someone has a hereditary disorder which may put them at increased risk of certain conditions.