Arterial Blood Gas Test
Overview
An arterial blood gas (ABG) test measures levels of oxygen and carbon dioxide in the blood, as well as the acidity (pH level) of the blood.
The test may be done for diagnostic purposes in a number of settings, including kidney or lung function, respiratory problems, and metabolic diseases.
The test is a very safe procedure, and problems are extremely rare.
Why it is Done
Why It Is Done
An arterial blood gas test may be ordered for the following reasons:
- To check lung, kidney, and metabolic functioning
- To help diagnose the cause(s) of breathing difficulties
- To check for evidence of cystic fibrosis or other disorders of the lungs and respiratory system
- To check the effectiveness of treatment for diseases of the lungs and respiratory system
- To check the effectiveness of oxygen therapy and determine if extra (or less) oxygen is needed
- To check the level of acidity (pH level) in the blood of people with heart or kidney failure, diabetes, or other conditions
How you Prepare
How You Prepare
Before you have an arterial blood gas test done, let us know about:
- All prescription and over-the-counter medications you are taking
- Any allergic reactions you have had in the past to medications or anesthesia
- Any bleeding problems you have ever had
- Any blood thinner medication, including aspirin, you have recently taken (or are taking now)
If you are on oxygen therapy, your oxygen may be turned off for a period of about 20 minutes before the procedure, unless you are unable to breathe without it.
How It Is Done
The blood sample for the test must be taken from an artery. It is usually taken from the radial artery in your wrist, but it may also be taken from the femoral artery in the groin or the brachial artery in the arm.
To prevent discomfort, we may inject local anesthetic to the area surrounding the artery before the sample is taken.
You will be seated during the procedure, with your arm extended. We will insert a small needle under your skin, into your artery, and draw blood until a syringe is filled. Once this is done, the blood will be taken immediately to a laboratory for analysis.
In some cases, more than one blood sample may be required, and we may insert a very thin, flexible hollow tube called a catheter in your artery so that we can easily withdraw blood again using a second or third needle.
We will place a cotton ball or gauze pad, followed by a bandage, over the injection site once the needle is withdrawn. We may ask you to apply firm pressure on the bandage for several minutes to staunch any bleeding, or we can assist you in doing this.
Results
An abnormal result from an ABG test may indicate that you:
- Are not getting enough oxygen through the bloodstream.
- Are not discharging enough carbon dioxide.
- Have a kidney function deficiency.
Causes of abnormal test results can include:
- Disease conditions such as kidney failure, diabetes, metabolic diseases, pneumonia, or other lung and respiratory disorders
- Severe infections
- Drug or alcohol overdose
- Dehydration
- Chronic nausea and vomiting
- Pain and anxiety
Abnormal arterial blood gas test results do not generally provide enough information by themselves to diagnose a condition. However, the test results can help pinpoint the source of problems when combined with the results of other types of tests and examinations.
What affects the Procedure
What Affects the Procedure
Factors that may affect your test results include:
- Fever
- Unusually low body temperature
- Having smoked or breathed in secondhand smoke shortly before the procedure
- Having breathed in a pollutant, such as carbon monoxide or paint remover, in a poorly ventilated area shortly before the procedure
Any of these circumstances may affect test results and make them less useful for diagnostic purposes. If you have a blood disease such as anemia, this will also influence your test results.
Disclaimer
If you have an emergency medical condition, call 911 or go to the nearest hospital. An emergency medical condition is any of the following: (1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.
This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.