The various groups were asked to state the preferred method of data collection (i.e. sampling conditions, timing in relation to treatment etc) and also state the reasoning for that specific method and preferably the relevant literature. At the Vienna meeting the data extraction group has agreed on the list of chosen CPI variables. For the preferred methods of data collection we will need to define standard operating procedures (SOPS). They should be as explicit as possible to make them really useful. Whenever such information is missing the data extraction group will further elaborate on this topic to come up with sound suggestions until the Glasgow assembly of registries. To enable data exchange between existing and future systems a strong focus on interfaces is needed. Interfaces are used for exchanging messages between electronic data systems. A widely accepted standard throughout Europe is HL7. Many countries in Europe have chosen HL7 as a national standard for data transmission in healthcare. The data extraction group has decided to use Version 3 of HL7 as the communication standard within the ERA EDTA area. The agreed upon CPI variables will be modelled and put into XML, a widely used electronic mark-up language. Examples mirroring the complete dialysis scenario are just being developed. Together with these standardised CPIs a preferred interface will be recommended for providers of clinical data management systems. There is still a lot of work ahead as one of the prerequisites of HL7 v3 is the usage of registered codes to make them easily readable. At the meetings it has been agreed to use registered codes whenever possible. Renal diagnosis and death codes used in the ERA-EDTA community since 1965 and modified in the 70ies need to be officially registered to make easy use of them. It can be expected that with the implementation of HL7 v3 an urgently needed harmonisation of electronic medical record systems will take place in the renal community. The implementation is a step to enhance sharing of data on an international level in the near future. Defined standards of communication together with the defined CPIs will enable providers of clinical data management systems in the field of nephrology to implement them and offer this modern tool to the renal community.