This paper reports on a collaboration between two research groups. The first group has studied Formalization of ANaesthesia knowledge (FAN). An aim in the knowledge formalization was support of diagnosis, but the diagnostic method to be used was itself not formalized at the time. The second group has developed a general framework for diagnostic reasoning. The framework is parametrized to account for the variation in diagnostic methods. In this paper the diagnostic framework is instantiated to describe the FAN diagnostic method. The parameters of the model are instantiated such that two requirements are fulfilled. Firstly the object knowledge in the FAN formalization is mapped to particular parameters. Secondly the parameters instantiations are such that the FAN reasoning method is reflected. The result of mapping FAN to the framework is twofold. Firstly, the FAN diagnostic method has been formalized. Secondly, it has been proven that the diagnostic framework is general enough to describe a diagnostic method as a generalization of which it was not designed.