ABG stands for arterial blood gas. It is a blood test that measures the amount of oxygen and carbon dioxide in your blood, as well as the acidity of your blood, also known as your pH balance. The test requires a sample from an artery in your body, not a vein, and is typically ordered in certain emergency situations. An ABG test can help diagnose and monitor conditions that affect your lungs and kidneys, as well as many other conditions that may upset your acid-base balance. Healthcare providers frequently order arterial blood gas (ABG) tests for the following settings or areas of medicine:

• Emergency departments
• Intensive care units
• Respiratory therapy
• Pulmonary function testing
• Anesthesiology
• Cardiology

An ABG test usually includes the following measurements:

• pH
• Partial pressure of oxygen (PaO2)
• Partial pressure of carbon dioxide (PaCO2)
• Bicarbonate (HCO3-)
• Oxygen saturation (SaO2)

If your ABG results are not normal, your healthcare provider will likely order more tests to make a diagnosis. In general, abnormal results may mean you have a problem with your lungs or kidneys or a metabolic disorder.