A blood sampling device has a vacuum tube and a sleeve provided with a two-ended needle. When one end of the needle is placed in a vein in order to take a blood sample, a seal in the vacuum tube is perforated by the second end of the needle so as to create suction for taking a blood sample. The sleeve...http://www.google.com/patents/US5337756?utm_source=gb-gplus-sharePatent US5337756 - Blood sampling device with a vacuum tube
