Arterial Blood Gases
An arterial blood gas (ABG) test measures the acidity (Reference pH Opens New Window) and levels of oxygen and carbon dioxide in the blood.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab and depend upon the elevation above sea level. Your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Results are usually available right away.
|Partial pressure of oxygen (PaO2):||
Greater than 80 Reference mm Hg Opens New Window (greater than 10.6 kPa)
|Partial pressure of carbon dioxide (PaCO2):||
35–45 mm Hg (4.6–5.9 kPa)
|Oxygen content (O2CT):||
15–22 Reference mL Opens New Window per 100 mL of blood (6.6–9.7 mmol/L)
|Oxygen saturation (O2Sat):||
The concentration of oxygen being breathed, called the fraction of inhaled oxygen (FiO2), is also usually reported. This is only useful if you are receiving oxygen therapy from a tank or are on a ventilator.
Many conditions can change blood gas levels. Your doctor will talk with you about any abnormal results that may be related to your symptoms and past health.
|By:||Reference Healthwise Staff||Last Revised: Reference May 30, 2012|
|Medical Review:||Reference E. Gregory Thompson, MD - Internal Medicine
Reference Robert L. Cowie, MB, FCP(SA), MD, MSc, MFOM - Pulmonology