The journey a blood tube takes from a patient's arm to the laboratory bench is governed by a strict biological clock. In transfusion medicine, “wrong blood in tube” is not simply a paperwork issue: a misidentified blood group can lead to a patient receiving incompatible blood and suffering an acute haemolytic transfusion reaction. But the NCL experience suggests this process failure is solvable, not an inevitable feature of how blood testing works. Pre-analytical errors and patient safety / Preanalitičke greške i bezbednost pacijenata. [2] Barak M, Jaschek R. A new and effective way for preventing pre-analytical laboratory errors.