Laboratory testing is pivotal to national Johne's disease programs developed by the Australian livestock industries. The Sub Committee for Animal Health Laboratory Standards (SCAHLS) has established standard diagnostic techniques and implemented a proficiency testing program through the Australian National Quality Assurance Program (ANQAP) for veterinary laboratories in Australia and New Zealand for a range of diseases. More recently SCAHLS has developed a Quality Plan for Johne's disease testing to enable the application of a national operation standard for laboratories performing Johne's disease diagnostic tests and for manufacturers supplying diagnostic reagents. The Quality Plan is based on standard diagnostic techniques, proficiency testing of laboratories and guidelines for assessing the performance of serological tests. The plan identifies issues which impact on test quality and describes actions required to maintain and promote a quality operating system. Implementation of the Quality Plan was initiated at an ANQAP Quality Assurance Workshop held in April 1998. Groups with particular responsibilities in the Quality Plan include; testing laboratories, ANQAP and manufacturers of diagnostic reagents. ANQAP conducts proficiency testing for serological tests and culture of faeces by distributing reference and 'unknown' samples, analysing results and publishing an Endorsed List of Laboratories. National serum panels are being assembled to facilitate objective and comparative assessment of the reproducibility of serological assays. Criteria have been established to monitor the performance of assays by diagnostic laboratories, kit manufacturers and ANQAP. It is envisaged that the Quality Plan will be reviewed regularly to enable continuous improvement of this operating system.