Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
It's usually done in the ER or hospital. An arterial sample is taken from the wrist and can sting more than a usual draw.
Why it's done
- Severe breathing trouble
- Possible DKA, poisoning, or sepsis
- Managing patients on breathing machines
Getting ready and what happens
- No preparation; done urgently.
How the test is done
- A needle draws blood from an artery, usually at the wrist; pressure is held afterward.
What the results mean
| Result | Typical range for adults |
|---|---|
| pH | 7.35 to 7.45 |
| Oxygen (PaO2) | About 75 to 100 mmHg |
| Carbon dioxide (PaCO2) | About 35 to 45 mmHg |
Normal ranges vary from lab to lab and can differ by age, sex, and pregnancy. Your report lists your lab's own range next to each result. A result a little outside the range is often not a problem.
Abnormal
Shows whether a problem is from the lungs or the body's chemistry, guiding emergency treatment.
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related tests
Sources
Last updated 2026-11-13.