What does ABG mean in the medical fields?

Arterial Blood Gas

An ABG is a blood test that can measure the amount of oxygen and carbon dioxide within your blood. Typically, this requires a doctor to draw blood directly from an artery, thus the term "arterial". Typically, the blood is drawn from an artery in your wrist, typically your radial artery. However, it can be drawn from other arterial sites, like the brachial artery. The physician will often use local anesthetic as well, to reduce the pain of the blood draw.