Purpose: Older patients are at high risk of hospital readmission, which has led to an increasing number of screening and intervention programs. Knowledge on implementing screening tools for preventing readmissions in emergency department (ED), where the primary focus is often the present-day flow of patients, is scant. The purpose of this paper is to explore whether a new screening tool for predicting readmissions and functional decline in medical patients>65 years of age could be implemented and its influence on cross-continuum collaborations between the primary and secondary sectors. Design/methodology/approach: The study took place in an ED in Denmark, in collaboration with the surrounding municipalities. An evaluation workshop with nurses and leaders from the ED and the surrounding municipalities took place with the aim of investigating the organizational changes that occurred in daily practice after the implementation of the screening tool. The workshop was designed and analyzed using cultural historical activity theory (CHAT). Findings: The results showed that it was possible to develop collaboration between the two sectors during the test period. However, the screening tool created different transformations for the municipality employees and in the ED. The contradictions indicated that the screening tool did not mediate a general and sustained transformation in the cross-continuum collaboration. Research limitations/implications: Screening tools are not objective, neutral or “acontexual” artifacts and must always be adapted to the local context and sectors. CHAT offers a perspective to understand the collective object when working with organizational transformations and implementation. Practical implications: The study have shown that screening tools are not objective, neutral or “acontexual” artifacts and must always be adapted to the local context. This is called adaption process. This adaption requires time and resources that should be taken into consideration from the beginning of introduction of new screens. Originality/value: This paper contributes with knowledge about CHAT which offers a way to understand the leading collective object when working with organizational transformations and implementation. CHAT focuses not only on the structural changes but also on the cultural aspects of organizational changes, which is important if we want to reach a sustained change and implement the new screening tool in different sectors.