Arterial blood samples are drawn from an artery. Common sites include the wrist, elbow, or groin. The area is cleaned with an antiseptic. A local anesthetic is injected to numb the area. A sharp, hollow needle is inserted into the artery.
Blood is collected using a syringe treated with heparin.
Heparin is a blood thinner that keeps the sample from clotting in the syringe. Pressure is applied to the collection site until bleeding stops. Usually no preparation is needed for an arterial blood sample. An arterial blood gas test can identify problems with the person's breathing and oxygen levels. It can also detect problems with the body's balance of acids and bases.