[1] An altered test, first suggested by Irving S Wright in 1952, has almost universally replaced the original method in contemporary medical practice.

If color fails to return, the test is considered abnormal and it suggests that the ulnar artery supply to the hand is not sufficient.

The radial artery is occasionally used as a conduit for bypass surgery, and its patency lasts longer in comparison to the saphenous veins.

[3] The utility of the modified Allen's test is questionable,[4] and no direct correlation with reduced ischemic complications of radial artery cannulation have ever been proven.

[6][7] In addition, the results of Allen's tests do not appear to correlate with distal blood flow as demonstrated by fluorescein dye injections.