GIVING BLOOD
'(<a href="http://www.j-archive.com/media/2011-10-11_J_26.jpg" target="_blank">Kelly of the Clue Crew preps to donate blood at an American Red Cross blood donation center in Washington, D.C.</a>)  Technically, the person who draws your blood is called this, from the Greek word for vein'
a phlebotomist