While the terms are often used interchangeably, there are important differences:

Proficiency testing:

– Organised and managed by an independent third party

– Includes the participation of a laboratory

– Uses its results to determine the performance of the participants

– Is a formal audit with a standardised report

– Represents objective evaluation criteria

Interlaboratory comparison (ILC):

– Carried out by mutual agreement between participating laboratories

– Can be carried out without an independent provider

– Used for comparison between laboratories, but not necessarily for formal accreditation

EQA-Scheme:

– German technical term for aptitude test

– Includes all elements of a formal proficiency test according to ISO 17043