User:Jwil224/Digital Allen's Test

Purpose
The Digital Allen's Test (Modified Allen's Test) is a clinical test to observe occlusion of the radial or ulnar arteries pertaining to blood supply to the hand.

Procedure
The patient and examiner may sit or stand. The subject is instructed to make a fist several times in succession in order to “pump” the blood out of the hand and fingers. The subject is then instructed to maintain a fist while the examiner compresses the radial artery with the thumb and the ulnar artery with the fingers. As the subject relaxes the hand, the examiner releases pressure from one artery at a time and observes the color of the hand and fingers.

Mechanism
The Digital Allen's Test works by observing the radial and ulnar arteries blood supply to the hand by applying pressure to the arteries one at a time.

Results
The hand will “blush” within 5 seconds if the vessel is normal. A delay in or absence of flushing of the radial or ulnar half of the hand and fingers is indicative of partial or complete occlusion of the radial or ulnar arteries, respectively.

Adverse Effects
This test should always be performed and compared bilaterally. Should a positive finding be present bilaterally, the examiner should consider brachial artery involvement.

History
The Allen's test as described in 1929 by Edgar V. Allen has been modified, adapted and complemented by other newer modalities but remains a first line standard test to evaluate the arterial supply of the hand.