ISO/IEEE 11073-10418:2013 establishes a normative definition of communication between personal telehealth International Normalized Ratio (INR) devices (agents) and managers (e.g. cell phones, personal computers, personal health appliances and set top boxes) in a manner that enables plug-and-play interoperability. Work done in other ISO/IEEE 11073 standards is leveraged, including existing terminology, information profiles, application profile standards and transport standards. The use of specific term codes, formats and behaviours in telehealth environments restricting optionality in base frameworks in favour of interoperability is specified. A common core of functionality of INR devices is defined in ISO/IEEE 11073-10418:2013. In the context of personal health devices, the measurement of the prothrombin time (PT) that is used to assess the level of anticoagulant therapy and its presentation as the International Normalized Ratio compared to the prothrombin time of normal blood plasma is referred to in INR monitoring. Applications of the INR monitor include the management of the therapeutic level of anticoagulant used in the treatment of a variety of conditions. The data modeling and its transport shim layer according to ISO/IEEE 11073-20601:2010 are provided by ISO/IEEE 11073:10418:2013, and the measurement method is not specified.