As a service to help laboratories with their quality, Proficiency Testing schemes need themselves to be able to demonstrate their quality. The International 'Standard' for the Operation of PT Schemes in ISO/IEC Guide 43 Part 1 (1997): 'The Development and Operation of Proficiency Testing Schemes'. This is further amplified by the ILAC Guide G13 'Guidelines for the Requirements of Providers of Proficiency Testing Schemes', which can be downloaded from the ILAC website. Many countries, including the UK, are starting to accredit PT scheme providers to ISO/IEC Guide 43, using ILAC G13 as an audit protocol. However, not all countries wish to accredit PT scheme providers, and not all PT scheme providers wish to be accredited. In order to reflect this situation, and to help laboratories look at the quality of all PT schemes, information on quality criteria for PT schemes is given on the eptis.
Examples from PT schemes which are designed to comply with ISO/IEC Guide 43 Part 1 can be seen on the LGC website.