The dynamic nature of clinical work makes it challenging to assess the usability of mobile information and communication technology (ICT) for hospitals. To achieve some of the realism of field evaluations, combined with the control of laboratory-based evaluations, we have conducted usability tests of prototypes in a laboratory custom designed as a full-scale ward section. Nurses and physicians acting out simulated clinical scenarios have used the prototypes. This paper reports on the general methodological lessons learned from three such formative usability evaluations. We have learned that the physical test environment, the test scenarios, and the prototypes form three variables that need to reflect a sufficient amount of realism and concreteness in order to help generate valid test results. At the same time, these variables are tools that can help control and focus the evaluation on specific issues that one wants to gather data on. We have also learned that encouraging reflection among participants and using detailed multi-perspective recordings of usage can help form a more precise understanding of how mobile ICT can accommodate clinical work.The current paper aims to inform work toward a best practice for laboratory-based evaluations of mobile ICT for hospitals.