[The knowledge of chagasic patients about their disease: collective construction of a research instrument and test of its applicability].

This article describes the collective construction of a research instrument (interview guideline) for investigating the knowledge of chagasic patients attended at the Chagas Disease Reference Center of the Oswaldo Cruz Foundation. A multi-professional team worked sequentially on six versions of the guideline for semi-structured interviews. The instrument aims collecting data for a qualitative approach to concepts and perceptions of the patients from the perspective of the human relationships in the context of life and health. It detects the individual experiences regarding the diseasing process, the knowledge about the disease (and the infection), the emotions, reactions, and affections. Some theoretical aspects were discussed based on sociological and anthropological practices used in public health actions. We performed a complete interview with a patient for testing and adjusting the instrument. The interview guideline was tested and showed to be a suitable instrument for investigating the knowledge of chagasic patients, covering many subjective and cognitive aspects. This knowledge can be a useful contribution to the development of strategies, actions and information material aimed at improving and humanizing the care delivered to Chagas disease patients.