Blood gas analysis, also called arterial blood gas (ABG) analysis, is a test that measures the amounts of oxygen and carbon dioxide in the blood, and the acidity (pH) of the blood.

An ABG analysis evaluates how effectively the lungs are delivering oxygen to the blood and how efficiently they are eliminating carbon dioxide from it. The test also indicates how well the lungs and kidneys are interacting to maintain normal blood pH (acid-base balance). Blood gas studies are usually done to assess respiratory disease and other conditions that may affect the lungs, and to manage patients receiving oxygen therapy. In addition, the acid-base component of the test provides information on kidney function.

Blood gas analysis is performed on blood from an artery. It measures the partial pressures of oxygen and carbon dioxide in the blood, as well as oxygen content, oxygen saturation, bicarbonate...