The Institute for Interlaboratory Studies (iis) is an independent organization that provides various types of interlaboratory studies (proficiency tests (PTs), round robins, cross checks, collaborative trials) for analytical laboratories. We are located in Spijkenisse, The Netherlands.

Our story started in 1994 when 23 SGS laboratories participated with the first internal QC program in the area of Petroleum Products. Thanks to the success and the added quality insights for the participating laboratories, it was decided to open up the program for external laboratories in 1996. SGS founded the Institute for Interlaboratory Studies as a trademark not much later.

For petroleum products, we successfully completed the accreditation procedure by the Dutch Accreditation Council RvA, in January 2000. Since then we have executed numerous PTs under this accreditation and all PTs we organize follow the same protocols as the accredited PTs. The number of participants at iis began to grow and we started to expand our sample preparation facilities.

Next to petroleum products, we started organizing PTs in the Consumer Retail category, such as banned products in Textile like AZO Dyes, OPP and Chlorinated Phenols and Migration tests for heavy metals in toys or in food contact materials. We added some of these Consumer Retail PTs to the accredited scope in 2013.

The institute organizes over 100 PTs annually with participants from all over the world. Among our participants there were more than 1900 different laboratories from over 120 countries actively participating in iis PTs in the last three years.

Our employees are highly qualified and experienced in the design, implementation and reporting of interlaboratory studies.