ALLEN TEST

Course overview

THE ALLEN TEST (AT) IS USED TO ASSESS COLLATERAL BLOOD FLOW TO THE HANDS. THE RADIAL ARTERY IS EASILY PALPABLE. THE NEED FOR THIS TEST ARISES FROM THE INABILITY TO PALPATE THE ULNAR ARTERY. BECAUSE THE ULNAR ARTERY CANNOT BE PALPATED, ITS PATENCY CANNOT BE ASSESSED, AND THEREFORE, COLLATERAL CIRCULATION OF THE HAND CANNOT BE CONFIRMED. IF THE RADIAL ARTERY NEEDS TO BE CANNULATED OR CATHETERIZED AND THERE IS A RISK FOR THROMBOSIS, THEN THE ALLEN TEST CAN HELP CONFIRM THAT THE HAND WILL MAINTAIN ADEQUATE BLOOD FLOW THROUGH THE ULNAR ARTERY AND COLLATERALS IN THE EVENT IT BECOMES OCCLUDED. A POSITIVE ALLEN TEST MEANS THAT THE PATIENT DOES NOT HAVE AN ADEQUATE DUAL BLOOD SUPPLY TO THE HAND, WHICH WOULD BE A NEGATIVE INDICATION FOR CATHETERIZATION, REMOVAL OF THE RADIAL ARTERY, OR ANY PROCEDURE WHICH MAY RESULT IN OCCLUSION OF THE VESSEL. THIS ACTIVITY REVIEWS THE EVALUATION OF THE ULNAR ARTERY USING THE ALLEN TEST AND DISCUSSES THE ROLE OF LABORATORY TECHNICIANS, RESPIRATORY THERAPISTS, NURSES, AND CLINICIANS IN PERFORMING THE TEST.