Each year a large number of deaths occur due to medical mistakes and wrong decisions within the healthcare system. Since blood- and other laboratory tests are essential methods to diagnose patients it is very important that these test are performed correctly. The Handbook for healthcare´s main goal is to reach out to medical staff to set guidelines and useful tools for example venous blood sampling. The aim of this study was to investigate if nurses follow the guidelines for venous blood sampling. A structured observational study was conducted in a large hospital in south of Sweden. The observations followed an observation checklist which was based on the guidelines. A total of 12 nurses were observed at 32 blood tests. Eight blood samples were canceled and the remaining 24 blood tests showed that the nurses had a relatively good adherence towards the Handbook for healthcare´s guidelines. This was particularly evident in the use of plastic gloves, control of patient identity, skin disinfection of the insertion site and to provide information to the patient. Despite the good adherence toward the guidelines there were deficiencies in other elements, such as the nurses kept the tourniquet on too long, used test tubes in the wrong order and did not turn the tubes properly after the blood sample. The results suggest a need for increased awareness among nurses about why and how certain tasks should be performed. The increased awareness could reduce pre- analytical errors and improve patient care.