Conformance testing has been studied extensively but the current state of the art varies very much in different software companies in the healthcare domain. In this paper we present findings of a survey of conformance testing of interface specifications in the healthcare domain. The survey was conducted among software companies and their customers, i.e. hospital districts, in Finland. The findings of the survey show that the quality of the applications should be improved, that there is a reluctance to use external interface testing services, and that software vendors do not adequately fulfill customers' requirements in relation to testing. However, conformance testing is considered to be very important and should be improved. The main contribution of this study is the analysis of the findings and we give some recommendations for healthcare organizations, software companies, and authorities to improve the conformance testing related to the interoperability of the applications.