This introduction to HL7 discusses the characteristics of the HL7 (Health Level 7) communication standard as is used to exchange information between clinical information systems. It explains the protocol using trigger events, the messaging layout in segments and also shows a sample message to be interpreted. This tutorial is meant to be used for anyone who wants to get a high level overview and idea of the HL7 standard in particular support and managerial healthcare IT professionals as well as people who work with these systems on a regular basis.