[Causal analysis and impact of a systematic error detected about consumption associated with trastuzumab].

Objective: determine the cause of the constant difference between the theoretical and real number of trastuzumab units consumed in an Intravenous Mixtures Unit.

Methods: was studied the manual and electronic full procedure about preparing mixtures with trastuzumab. Was performed by visual observation and review of quantitative monitoring data from the electronic preparation support and safe system of the application Farmis-Oncofarm®.