ABG: Arterial Blood Gas
ABG stands for Arterial Blood Gas. It refers to a test that is performed to measure the levels of the oxygen and carbon and acidity (pH) in the blood of an artery. This test checks how efficient your lungs are in moving oxygen into the blood and removing carbon dioxide from the blood. When blood passes through lungs oxygen from the air present in the lungs moves into the blood and carbon dioxide from the blood moves out into the lungs.
In this test, blood is drawn from an artery before it enters into body tissues. This provides you with the following information or it measures:
Partial pressure of oxygen (PaO2): It is the pressure of oxygen dissolved in the arterial blood. The pressure of oxygen shows how efficiently oxygen is moving into the blood from the lungs.
Partial pressure of carbon dioxide (PaCO2): It is the pressure of carbon dioxide dissolved in the arterial blood. It shows how efficiently the carbon dioxide moves out of the blood into the lungs.
pH: It is a measure of the hydrogen ions (H+)/pH in the blood. pH less than 7 indicates acidic solution and more than 7 indicates basic/alkaline solution. In general, arterial blood pH ranges from 7.38 to 7.42. So, it is slightly basic in nature.
Bicarbonate (HCO3): It is a chemical (buffer) that helps maintain the pH of blood. It prevents blood from becoming too acidic or too basic.
Oxygen content (O2CT) and oxygen saturation (O2Sat) values: O2 content value is the measure of the amount of oxygen in the blood. Oxygen saturation value tells how much of the total hemoglobin in the red blood cells is carrying oxygen.
In general, the normal values of an ABG test are as follows:
- pH= 7.38 – 7.42
- Bicarbonate: 22 – 28 mEq/L
- Partial pressure of oxygen: 75 – 100 mm Hg
- Partial pressure of carbon dioxide: 38 – 42 mm Hg
- Oxygen saturation: 94 – 100 percent