“The topics of the Listening sub-tests are chosen carefully to be accessible to all candidates of the OET. They are of general medical interest and cover a wide variety of issues. The OET is a test of English, not of medical knowledge, and the test developers are careful in the test design to minimise areas where candidates may use prior knowledge rather than language skills to respond.
“Topics will vary from administration to administration and while some topics may include content that is familiar to one particular health practitioner’s area of experience and expertise, the language tasks and questions associated with the texts are designed to test language knowledge and ability, over and above, the candidate’s knowledge of that field. In other words, correct responses cannot be simply ‘predicted’ because a candidate has experience in that area. Listening texts are selected for their concentration of content of a general health literacy nature; elements that can be considered common across multiple professions.”
(From OET Listening Sub-test: Test Information PDF)