Medical Health Encyclopedia

Blood gases

Injury Disease Nutrition Poison Symptoms Surgery Test Special Topic

1 2 5 A B C D E F G H I J K L M N O P Q R S T U V W X

Blood gases test

Overview Risks Results

Blood gases

Definition:

Blood gases measure the pH (acidity), oxygen content, and carbon dioxide content of the blood. Usually, blood gases are used to analyze the arterial blood. In rarer cases, venous blood may be used.

Alternative Names:
Arterial blood gas analysis; ABG

Text Continues Below

---

How the test is performed:

The test is performed by collecting a sample of blood from an artery. Using a small needle, the sample may be collected from the radial artery in the wrist, the femoral artery in the groin, or the brachial artery in the arm.

Before blood is drawn, the circulation to the hand may be tested (if the wrist is the site). After the blood is drawn, pressure is applied to the puncture site for at least 5 minutes to completely stop the bleeding.

The test must be sent to the laboratory for analysis immediately, or the accuracy of the results cannot be guaranteed.

How to prepare for the test:

There is no special preparation. If the person receiving the test is on oxygen, the oxygen concentration must remain constant for 20 minutes preceding the test. If the test is to be taken without oxygen, the oxygen must be turned off for 20 minutes before the sample is taken to ensure accurate test results.

Infants and children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)