Any test or calibration laboratory, in order to ensure its performance over time, needs to participate periodically in interlaboratory proficiency tests. As a matter of fact the interlaboratory proficiency test is an effective tool for estimating laboratory performance on specific tests or measurements and allows an accurate and continuous monitoring. In this way the laboratory can ensure the trust of its customers by validating its uncertainty claims and its metrologic traceability. In addition, interlaboratory proficiency tests are increasingly required by accreditation bodies as a condition for obtaining and maintaining the specific accreditations of testing or calibration procedures.

One of the most common schemes is the sequential evaluation test scheme: it requires one or more objects (samples) of the test to be distributed sequentially to participating laboratories, that perform tests or measurements according to their specific procedures (accredited or not accredited). The samples are then returned to the provider who verifies their suitability for final assessments once they have been processed by all participating laboratories.

All the results (certificates issued) are then collected and statistically analyzed by the provider who writes and distributes a final report showing the assessment of the performance of all participants.

SA quality for metrology is an Accredited Proficiency Test Provider according to ISO/IEC 17043:2010 standard by the Italian accreditation body Accredia that issued the Accreditation Certificate number PTP 0024P.