Allen Test (hand)
“The Allen test is used to determine the patency of the vessels supplying the hand. The clinician compresses both the radial and ulnar arteries at the wrist (Fig. 18-61), and then asks the patient to open and clench the fist three to four times to drain the venous blood from the hand. The patient is then asked to hold the hand open while the clinician releases the pressure on the ulnar artery and then the radial artery. The fingers and palm should be seen to regain their normal pink color. 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. A distinct difference in the filling time suggests the dominance of one artery filling the hand.”1