Which test assesses patency of the radial and ulnar arteries by compressing at the wrist and observing color return?

• A. Adson's test
• B. Finkelstein's test
• C. Phalen's test
• D. Allen's test

Answer: (D)

Allen's test is used to evaluate whether both the radial and ulnar arteries can supply the hand adequately when one is occluded. The idea is to compress the two arteries at the wrist to blanch the hand, then release one artery and observe how quickly color and blood flow return to the hand. If color returns quickly, it shows good collateral circulation from the other artery, meaning one artery can be used for procedures without risking hand ischemia. If color does not return promptly, that suggests poor collateral flow or an occlusion, indicating potential risk if the artery is cannulated or harvested.

This test is distinct from the others: Adson's test screens for thoracic outlet compression of the subclavian artery, Finkelstein's test checks for De Quervain's tenosynovitis, and Phalen's test screens for carpal tunnel syndrome.