Allen's test

With the Allen test ( after the American physician Edgar Van Nuys Allen) of the palmar arch palmar arch, the radial artery and the ulnar artery can be tested for circulatory disorders. All the test is performed prior to arterial puncture, to ensure the circulation of the hand even in a closing of the punctured artery. Furthermore, the Allen test is used as a clinical method of investigation in advance of a planned removal of a radial artery flap to a possible unilateral arterial supply, ie to recognize a blood supply only through the radial artery and ulnar artery, the hand. Its diagnostic value is controversial. More specifically, an arterial flow determination of the two arteries by ultrasonography.

Depending on the problem - circulatory disturbance of an artery or unilateral blood supply to the palmar arch - the test is carried out according to the following scheme:

• Circulatory disturbance of an artery: case, both arteries are pushed away, the blood pumped into the hand by repeatedly opening and closing the hand peripherally from his hand and then dissolved the closure of the test artery. In general, the hand should fill under normal conditions within a few seconds with blood. If this is not the case, are circulatory disorders in the artery tested before, mostly atherosclerosis.

• Unilateral blood supply to the palmar arch: Here, the marks of a feeding artery and the observation of the blood supply to the hand. There must be no white coloration of the hand movement that speaks for an insufficient blood supply through the uncompressed artery else. The cause anatomical peculiarities of blood supply (eg the absence of anastomoses of both coverage areas ) or circulatory disorders are possible.

Original Description

• Allen EV: thromboangiitis obliterans: methods of diagnosis of chronic occlusive arterial lesions distal to the wrist with illustrative cases. Am J Med Sci 1929; 2:1-8.