Introduction: The Patient Centered Assessment Method (PCAM) is a 12-item tool inspired by the biopsychosocial model of illness. It contains four themes: Health and Well-being, Social Environment, Health Literacy and Communication, and Service Coordination. It supports holistic patient conversations, with the aim to determine and register biopsychosocial needs and follow-up actions. This is an important precondition for working towards the right type of integrated care. Although it is a promising and largely validated tool, there is uncertainty about the theoretical constructs that are measured. Furthermore, the value for primary care is limitedly assessed. This study aimed to overcome these knowledge gaps.Methods: A Dutch version of the PCAM was created. Seven general practices subsequently tested the Dutch PCAM, as tool to support a person-centered assessment for chronically ill, as one of the components of the TARGET program. In total, 228 PCAMs were completed. We performed a factor analysis to determine what theoretical constructs are measured by the PCAM. Cronbach’s alpha was computed to study reliability of the tool. These quantitative insights were compared with the insights retrieved from – largely individual – interviews with 15 professionals who used the PCAM. We developed a semi-structured interview guide, and analyzed the transcripts thematically and inductively. Results: The 228 included patients were on average 73 years old, more than 70% was female and more than 80% had at least two chronic conditions. The factor analysis revealed that each of the four PCAM themes measures a separate construct. The Cronbach’s alpha of the complete tool was adequate (0.83). In the interviews, professionals reported that the PCAM is valuable for scientific measurement of holistic patient needs. Moreover, the PCAM was valued for planning actions with patients. There was also criticism on the PCAM. Professionals argued that completing the PCAM from a professional perspective – rather than by the patient – conflicts ...