Interlaboratory comparison measurements

Comparison of laboratory results with the results of the reference laboratory as representative of a recognized authority


Interlaboratory comparisons (ILC) as part of proficiency testing are widely used by calibration and testing laboratories, as well as by other laboratories conducting measurements or inspections. Participation in ILC is an essential part of demonstrating the quality of measurement results. ILC is one of methods assuring the professional level of the activities and services provided by metrological laboratories.

Fundamentals of ICM

The process of ILC is focused on comparison of results of laboratory against assigned (reference) value and evaluation of laboratory performance against pre-established criteria, and may include mutual comparison of measurement results in case of multiple participants. Assigned values in case of calibration laboratories are mostly determined on the basis of measurement results of reference laboratory, which is recognised authority for specified field of measurement. From the participant’s  point of view, ILC may be viewed as a tool for demonstration of quality of activities, credibility, equivalency of measurement results, identification of existing issues and areas for improvements, however it may also be used for educational purposes. From the point of regulatory authority (national metrology institutes, national accreditation services, etc.), ILC is used as a tool for demonstration of competence of accredited laboratory or other subject authorised to conduct specific activities (according to national legislation), including assessment of measurement uncertainties declared by laboratory (CMC – Calibration and Measurement Capabilities). Successful performance in ILC is one of the requirements for obtaining accreditation and may be required for obtaining authorisation to conduct specific activities (according to national legislation).

Accreditation of ICM 

SLM included organisation of ILC into scope of provided services in 2001.  Since 2004,  competence to organise ILC is further demonstrated by an accreditation awarded by Slovak National Accreditation Service (SNAS). The programs of the interlaboratory comparisons are organized in accordance with the requirements of the international standard ISO/IEC 17043: 2010 – Conformity assessment – General requirements for proficiency testing.

Client zone ICM

Login to client zone ICM here


More information:

Mgr. Laura Grúberová, tel: +421 907 695 804, e-mail:

Responsible for content Ing. Kamila Vitkovičová.