Arterial Blood Sample

An arterial blood sample is a small amount of blood collected from an artery. The blood is then used for testing in the laboratory.

Who is a candidate for the test?

Arterial blood samples are most often used for an arterial blood gas, or ABG, test. ABGs are a series of blood measurements that are ordered as a single test. This test is primarily used to check lung function and acid levels in the body.

An arterial blood sample may also be done to obtain blood for a CHEM-20 or CHEM-7. These tests look at a number of chemicals in the blood serum. Blood cultures for aerobic or anaerobic organisms may also be done on an arterial blood sample. These tests look for bacteria and other organisms in the blood.

How is the test performed?

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.

What is involved in preparation for the test?

Usually no preparation is needed for an arterial blood sample.

What do the test results mean?

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.

An analysis of blood chemistry can reveal a lot about problems in specific cells and tissues. The provider will discuss results with the individual.

Blood cultures can be used to identify organisms that are causing a body-wide infection.