This paper examines some fundamental issues pertaining to the use of, as well as to the distinctive characteristics of, information technology in relation to the development of information systems within the UK National Health Service (NHS). The paper refers to the current Resource Management Initiative in the NHS, which involves the fabrication of information systems to connect medical activity to resource usage, and thus to costs. Examining the features of some of the rival inscriptions undergoing development to make this connection visible, the paper highlights the properties of information technology in enhancing their mobilization. It also addresses the immutability and combinability of these inscriptions, and discusses some of the implications, in terms of medical practice and knowledge, which may follow from their use.