Organisational communication perspectives provide a framework for examining the impact of new Computerised Physician Order Entry (CPOE) systems on health care organisations. The aim of this study was to utilise performance metrics (volume of telephone/fax calls and the management of unfulfilled test requests) as a way of monitoring the impact of a new CPOE system on the communication (synchronous and asynchronous) interface in the Central Specimen Reception (CSR) area of a pathology laboratory service. The total number of outgoing and incoming calls rose considerably after the implementation of the new system. The number of unfulfilled test requests initially increased in the implementation period and thereafter fell to below pre-implementation levels. There were significant differences in the relative proportion of duplicate (69%-35%) and rescheduled requests (4%-24%) between the pre- and post-periods. Performance metrics, can be relevant for measuring and monitoring changes in communication processes. This is important with CPOE systems whose introduction can have unexpected consequences requiring early detection and action.