THE ALLEN TEST- AN INVESTIGATION OF ITS ACCURACY BY FLUORESCEIN ANGIOGRAPHY

Six consecutive patients whose clinical Allen test suggested a non-patent radial artery have been investigated by intra-arterial fluorescein angiography. Cannulation of the radial artery and injection of fluorescein typically perfused only the thumb and thenar eminence. Occlusion of the ulnar artery, leaving the radial artery as the dominant supply, resulted in fluorescein perfusion of the entire hand. It is concluded that the Allen test is of no clinical value. The test described by Allen (1929) for assessment of arterial patency in occlusive peripheral vascular disease has become a standard technique for examining blood flow to the hand. The original technique has been modi-fied (Ejrup et al. 1966), but the principle remains the same. Although Allen did not define a positive or negative result, common usage has determined that a negative result means that the skin distal to the site of arterial occlusion during the test rapidly becomes hyper