Arterial Blood Gas Test

The arterial blood gas test is also known as an oxygen saturation test. The purpose of the blood gas measurement is to evaluate the oxygenation and the acid/base status of the patient. The arterial blood gas test measures PaO2 or partial pressure of oxygen, PaCO2 or partial pressure of carbon dioxide, pH, HCO3 or Bicarbonate and O2CT or oxygen content. The physician will take the blood for an arterial blood gas test from an artery rather than a vein as with most other blood tests.

What makes the arterial blood gas test distinct from other blood examinations is that it draws blood from an artery rather than a vein. When blood is drawn from the vein, the blood has already passed through the tissues where carbon dioxide is produced and oxygen used up. When blood is drawn from the artery instead, the oxygen is still present in the blood and carbon dioxide not yet produced.

The arterial blood gas test involves testing the level of oxygen in the blood, and there are a number of conditions that it might be used to diagnose. These can include lung diseases and breathing problems such as cystic fibrosis, asthma, chronic obstructive pulmonary disease or COPD and others. It can also help to determine whether or not lung disease treatments are working. This test can help a physician determine if mechanical ventilation is necessary for someone having difficulty breathing, and can also determine if the right amount of oxygen is being delivered in patients who are receiving mechanical ventilation. This exam can also serve to measure the blood's acid-base level in people who have kidney failure, heart failure, uncontrolled diabetes, severe infection, sleep disorders or who have overdosed on drugs.