The nurse must ensure sufficient perfusion of the ulnar artery prior to attempting to draw blood from the radial artery. This is achieved by performing the Allen test in which the nurse occludes both the radial and ulnar artery until the hand blanches then releasing pressure from the ulnar artery. If perfusion returns, the nurse can proceed with the blood draw because it indicates the patient will be able to perfuse his or her hand if the radial artery is damaged. If perfusion does not return, the nurse does not proceed with the blood draw and should assess the other radial artery. Although it is appropriate to cleanse the site with hospital-approved antiseptic and place the patient’s arm on a flat, level surface with the wrist slightly extended, these are not the initial interventions to be performed. A tourniquet is used in venipuncture, not arterial punctures.