Today, technologies are being introduced into historically established settings, which change the conditions for work as well as for work-integrated learning. In health care, electronic patient records (EPRs) has been implemented during the last decades to serve as a tool for planning, decision making and evaluation of care work. The overall aim of the research presented in this thesis is to analyse the complex actions and interactions that occur when EPRs are used in health care practice. Analytically, such an interest is pursued employing a socio-cultural perspective on workplace studies, where the use of technology is studied in action. Through three separate studies, practical actions and practical use of EPRs have been examined and the empirical data draws on observations, video-recordings, audio-recordings and documents from a hospital ward in Sweden. The result shows that technologies such as EPRs both offer and presuppose standardization of terminologies and information structures. This, however, does not mean that EPRs completely format and structure information, or that it is driven by its own logic. When staffs comply with a set of standards, transformations of those standards will gradually occur. Those transformations are collective achievements and since each professional involved act in a conscious and active manner, this affects the use of standards as well as the development of collective proficiency. The results also demonstrate that meaning making in(through) the use of EPRs presupposes extensive knowledge of the indexicality of categories, something that originates in the participants‘ shared institutional history. It is in the process of reliving, creating and exposing the meaning of information, that health care professionals actually bring information in EPRs to life. In further development of EPRs that exceeds institutional and even national boundaries it is important to see this development not as solely technical or organizational questions. To develop systems that enhance the possibilities for professionals in different institutions with different professional domains to make sense of standardized information may be a much more  demanding task than it seems to be. Such boundary-crossing systems are nevertheless of great importance for the further development of health care practice.