After a definition of the various emergency situations, vital or organizational, the paper describes the process of urgent laboratory tests requests from the medical prescription until the return of the interpreted results to the clinician. The intervention options of the various professionals to optimize and assure the control of the process 24 hours a day and 7 days/7 are presented. Then, a list of validated available stat tests is proposed. It recovers the main disciplines which have a direct link to bring the help to the clinical teams in responsibilities of critical situations. These propositions must be adapted to the conditions of laboratory local environment.