Which of the following is the site of choice for obtaining samples for an arterial blood gas (ABG) ?

A) Radial artery
B) Brachial artery
C) Femoral artery
D) Popliteal artery

The radial artery is the safest,most accessible site for puncture;it is superficial,is not adjacent to large veins,and usually has adequate collateral circulation by the ulnar artery.Its use is relatively painless if the periosteum is avoided,and it is used when Allen's test is positive.The brachial artery has reasonable collateral blood flow but is less superficial,is more difficult to palpate and stabilize,and carries increased risk for venous puncture;its use results in increased discomfort.The femoral artery should not be used by nurses without specialized training.The popliteal artery usually is not used.