Definition:
Arterial blood gas (ABG) is a medical test that measures the levels of oxygen (O2), carbon dioxide (CO2), and pH (acidity) in a sample of arterial blood.
Purpose:
ABG tests are used to:
- Assess lung function and oxygenation
- Evaluate acid-base balance
- Diagnose respiratory conditions, such as pneumonia, asthma, and COPD
- Monitor the effectiveness of treatments for respiratory diseases
Measurements:
The following parameters are typically measured in an ABG test:
- pH: A measure of acidity or alkalinity
PaO2 (partial pressure of oxygen): The pressure of oxygen dissolved in the blood PaCO2 (partial pressure of carbon dioxide): The pressure of carbon dioxide dissolved in the blood HCO3- (bicarbonate): A chemical that helps regulate blood pH Oxygen saturation (SaO2): The percentage of hemoglobin in the blood that is carrying oxygen