Arterial Blood Gases
How To Prepare
Tell your doctor if you:
- Have had bleeding problems or take blood thinners, such as
aspirin or warfarin (Coumadin).
- Are taking any
- Are allergic to any medicines, such as those used to
numb the skin (anesthetics).
If you are on oxygen therapy, the oxygen may be turned off
for 20 minutes before the blood test. This is called a "room air" test. If you
can't breathe without the oxygen, the oxygen will not be turned off.
Talk to your doctor about any concerns you have regarding the need for
the test, its risks, how it will be done, or what the results may mean. To help
you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
A sample of blood from an artery is
usually taken from the inside of the wrist (radial artery), but it can also be
taken from an artery in the groin (femoral artery) or on the inside of the
arm above the elbow crease (brachial artery). You will be seated with your arm
extended and your wrist resting on a small pillow. The health professional
drawing the blood may rotate your hand back and forth and feel for a pulse in
A procedure called the
Allen test may be done to ensure that blood flow to your hand is normal. An
arterial blood gas (ABG) test will not be done on an arm used for
dialysis or if there is an infection or inflammation
in the area of the puncture site.
The health professional taking a
sample of your blood will:
- Clean the needle site with alcohol. You may be given an injection
local anesthetic to numb that area.
the needle into the artery. More than one needle stick may be
- Allow the blood to fill the syringe. Be sure to breathe
normally while your blood is being collected.
- Put a gauze pad or cotton ball over the needle site as the needle
- Put a bandage over the puncture site and apply firm
pressure for 5 to 10 minutes (possibly longer if you take blood-thinning
medicine or have bleeding problems).