An arterial blood gas (ABG) test measures the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery. The ABG analysis is performed to check how well the patient's lungs are able to move oxygen into the blood and remove carbon dioxide from the blood. Take your ABG test with our online arterial blood gas interpreter. The test is commonly known as a blood gas analysis or arterial blood gas (ABG) test. This analyzer should not substitute for clinical context.