When Preparing to Draw Blood for a CBC on an Elderly

Essay

When preparing to draw blood for a CBC on an elderly female patient, the medical assistant sees a large vein in her antecubital area. The MA quickly cleans the site, applies a tourniquet, and attempts a blood draw. She is not successful with the blood draw, even though she feels certain that the needle is within the vein.What important step did the MA skip when she started the process that may have resulted in a successful blood draw?