What it means
The examiner presses on both the radial and ulnar arteries at the wrist while the client makes a tight fist, so the hand turns pale. The client opens the hand and the examiner releases only the ulnar artery: if warmth and color return quickly, the ulnar artery can supply the hand on its own. It is done before puncturing the radial artery for a blood gas or an arterial line. It is named after Edgar Allen, an American physician.
For the nurse
If color is slow to return, do not use that radial artery; report it and try the other wrist.
At a glance
| Also written | Allen's test, modified Allen test |
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Related terms
arterial blood gas
A blood test from an artery that measures oxygen, carbon dioxide, bicarbonate and the blood's pH.
artery
A blood vessel that takes blood from the heart out to the body.