The global medical process is a chain of different medical multidisciplinary procedures. The success in global Patient Safety will depend on the Safety of the consecutive medical processes that intervene in this complex system. Laboratory data is an essential part of health care, indeed it is used in 70% of clinical decisions. Inappropriate laboratory test over requesting is extremely frequent. The prevalence of under requesting has been less studied. The consequences of under requesting are clear, we are missing a diagnosis. Inappropriate over requesting can result not only in a problem...