Transformations in collaborative work due to the introduction of new technology are inevitable, but are often difficult to study. In this paper, we consider the patterns of transformation that are seen in a patient-physician relationship based on the introduction of homecare monitoring equipment. We report findings from interviews and fieldwork with patients and physicians participating in a clinical experiment of homecare monitoring. By studying both the group of patients who receive homecare-based treatment and the control group we were able to identify transformations in the collaborative activity as caused by the homecare monitoring technology. We apply activity theory as a theoretical basis for this analysis. We consider the implications of these findings for the design of pervasive health monitoring technologies.