Arterial Blood Gas (ABG) Test
Reviewed
This test measures oxygen and carbon dioxide levels, pH, and often bicarbonate in a blood sample taken from an artery. It helps diagnose serious lung or kidney disorders and monitor treatment for breathing or acid-base problems.
Preparation and collection
Tell your provider about all the medicines and supplements you take. Do not stop any medicine unless your provider tells you to. If you take blood thinners (including aspirin), ask your provider whether you should stop them before the test. If you are on oxygen therapy, your oxygen may be turned off for about 20 minutes before the test, but only if you can breathe without it.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- Arterial puncture is more uncomfortable than a blood draw from a vein.
- You may have some bleeding, bruising, or soreness at the puncture site.
- Very rarely, the needle may damage a nerve or the artery.
- You may be told to avoid lifting heavy objects for 24 hours after the test.
- An ABG test alone usually cannot provide a diagnosis; your provider will likely order more tests if results are not normal.
What to do next
Your provider will explain what your results mean for your health. Abnormal results may lead to additional tests for your lungs, kidneys, or for metabolic disorders.
Evidence source
U.S. National Library of Medicine: Arterial Blood Gas (ABG) Test