Arterial Blood Gas (ABG) Test Test
An arterial blood gas (ABG) test measures oxygen and carbon dioxide levels in your blood, as well as your blood's acid-base balance. It helps check how well your lungs and kidneys are working.
What this test measures
An ABG test measures oxygen saturation (O2 Sat), partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), acid-base balance (pH level), and sometimes bicarbonate (HCO3). These values show how well your lungs move oxygen into your blood and remove carbon dioxide, and how well your kidneys help maintain pH balance.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Frequently asked questions
What does an ABG test measure?
It measures oxygen and carbon dioxide levels in your blood, as well as your blood's acid-base balance. This includes oxygen saturation, partial pressure of oxygen and carbon dioxide, pH, and sometimes bicarbonate.
Why is blood taken from an artery for this test?
Blood from an artery has higher oxygen levels than blood from a vein, which is needed for accurate measurements of oxygen and carbon dioxide.
What are the normal ranges for ABG test results?
According to MedlinePlus, typical normal ranges are: oxygen saturation 95-100%, PaO2 75-100 mmHg, PaCO2 35-45 mmHg, pH 7.35-7.45, and bicarbonate 22-26 mEq/L. However, ranges may vary by lab.
What can abnormal ABG results mean?
Abnormal results may indicate problems with your lungs or kidneys, or a metabolic disorder. However, an ABG test alone usually cannot provide a diagnosis, so your provider will likely order more tests.
How is an ABG test used?
It helps diagnose serious lung and breathing problems, kidney disorders, and to check if treatment for these conditions is working.
Related lab tests
Sources
- MedlinePlus: Arterial Blood Gas (ABG) Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.