Alpha-1 Antitrypsin

Alternate Names : Alpha-1 Antitrypsin, AAT

This test measures the amount of the protein alpha-1 antitrypsin (A1AT) in the bloodstream. A1AT is made by the liver and released into the blood. It blocks the action of certain enzymes that are released by dying cells. These enzymes can cause the breakdown of key proteins in the body.

Who is a candidate for the test?

This test is normally performed on people with a family history of emphysema. These individuals often have an inherited deficiency of A1AT. The test may may also done to diagnose swelling, severe infection or tissue or bone death.

How is the test performed?

In order to measure the amount of alpha-1 antitrypsin in the blood, a blood sample needs to be taken. It is usually obtained from a vein on the forearm or hand. The skin over the vein is first cleaned with an antiseptic. Next, a strong rubber tube, or "tourniquet", is wrapped around the upper arm. This enlarges the veins in the lower arm. A thin needle is inserted gently into a vein and the tourniquet is removed. Blood flows from the vein through the needle. It is collected in a syringe or vial and sent to the lab for testing. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding.