How to Draw an Arterial Blood Gas

Arterial blood gas is an emergency investigation sent in a patient who is breathless or in kidney failure. And since it is an emergency, one has to be really quick in sending one. This method is followed in rural hospitals which do not have their own lab. Methods may vary according to the country.


  1. 1
    Keep an ice pack ready and labelled with the patient's name. Arterial blood is prone for clotting and needs to be put in an ice pack as soon as it is drawn.
  2. 2
    Take a 2cc syringe and load about 0.2cc of heparin solution in it. Heparin prevents clotting but too much of it can interfere with the results.
  3. 3
    Check the radial pulsation of the patient. Check the pulse with the tip of your fingers and look for the spot where the pulsations hit your fingertips the most. It's easier if the patient's wrist is hyper extended.
  4. 4
    Insert the needle into the spot which you have found in step 3. Go at an angle of 45-60 degrees to the skin.
  5. 5
    Look for signs you're in the artery. You will know that you are in the artery when bright red blood enters your syringe. The blood is pulsatile. If the blood does not pulsate and is dark red, it means that you are in a vein instead.
  6. 6
    Once you are in the artery, draw about 1.5-2 cc of blood. Bring the needle out, keeping a ball of cotton on the puncture wound. Ask the patient or his by stander to apply pressure for about half a minute.
  7. 7
    Make sure there are no air bubbles in the syringe.
  8. 8
    Bend the needle and then recap it to prevent exposing it to air. Bending the needle prevents you from getting pricked.
  9. 9
    Immediately put the syringe into the ice pack and send it to the lab.


  • If you get the artery in your first attempt, you can change the direction of the needle slightly without bringing it out.


  • Make sure not to prick yourself.

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Categories: Cardiovascular Health and Blood Pressure