ComMA (an abbreviation of Component Modeling and Analysis) is an approach for modeling components and their interfaces in an implementation agnostic notation. The approach is supported by the open-source tool Eclipse CommaSuite. It supports, for instance, model validation and monitoring to check whether the execution of an implementation conforms to the specification. In this paper, we describe how ComMA models can be reused for online Model-Based Testing (MBT). An innovative feature of ComMA is its ability to construct a test application based on existing component and interface models, which enables reuse and avoids clones. This avoids well-known problems with MBT such as the validation and maintenance of large test models. The ComMA MBT approach has been applied and improved based on an application at Philips IGT in the context of a medical system. We report on our experiences and lessons learned.