Allen Test

Published July 2, 2026 Read time 2 min read Readers 1

What is the "Allen Test" used for?

The Allen test (or as it called Fist-Closure Test) is used to determine the patency of the vessels supplying the hand (the radial and ulnar arteries).

The patient is seated with the elbow flexed and forearm supinated, and raises his or her arm above the horizontal plane.
The examiner grasps the patient’s wrist and applies finger pressure to block the vascular supply from the radial and ulnar arteries.
The patient then makes a fist three to four times so as to force the venous blood out of the hand via the posterior veins.
After 1 minute, the patient lets the arm hang down and opens the now pale hand.
The examiner now releases compression, first from one artery then from the other.
This procedure is repeated with the radial artery released and compression on the ulnar artery maintained.

Normal filling time is usually less than 5 seconds ( Rapid, uniform reddening of the hand in the areas supplied by the respective arteries).
If the return of color to the palm is significantly prolonged after the release of either artery, the examiner should conclude that perfusion from that artery is reduced ( positive Allen Test ).