Which artery is most favored for arterial blood gas (ABG) sampling?

• A. Radial artery
• B. Brachial artery
• C. Femoral artery
• D. Carotid artery

Answer: (A)

For ABG sampling you want a site that is easy to access, reliable to puncture, and safe for the patient. The radial artery at the wrist fits all of these. It lies close to the skin, making cannulation straightforward, and you can reliably feel the pulse to guide needle placement. Equally important is the hand’s collateral circulation through the ulnar artery via the palmar arches; this means the hand remains well perfused even if the radial flow is momentarily compromised during the procedure. To protect against complications, you check that collateral flow is adequate before you sample—this is done with an Allen test. If the test shows good ulnar supply, you can proceed; if not, you’d choose another site such as the brachial or femoral, avoiding carotid due to higher risk. After taking the blood, apply firm pressure for several minutes to prevent hematoma and avoid repeated sampling from the same artery toosoon. These factors make the radial site the preferred choice for ABG testing.