| Description: | To measure the level of fresh air (oxygen), exhaust gas (carbon dioxide), and acid in the blood. |
| Test: | A small sample (about 5 mL or 1/3 of a tablespoon) of blood will be drawn from an artery, either the wrist or the elbow. |
| Length of Time: | Approximately 15 minutes. |
| Preparation: | Notify the technician if currently taking anti-coagulation (blood thinner) medication. Eat a regular breakfast/lunch and drink plenty of fluids. |