it is really called arterial blood gas test (spelling is probably wrong), instead of the vein usually used for regular blood tests, they go thru your wrist down to the artery there to withdraw the blood. it hurts a lot :thumbup:. at least 10 times the regular blood test. i was almost in tears :sad:when he finally withdrew the needle, whew!!!!! you didn't have to do this? i wonder if it matters on our ages? the older we are the more tests are done???? ugh!!!!