Proficiency testing PT & inter-lab. comparison | 7.7 Ensuring the validity of results (A).

Clause 7.7 in the international standard ISO/IEC 17025:2017 specifically addresses ensuring the validity of results. Subsection B of Clause 7.7 focuses on proficiency testing and inter-laboratory comparisons as means to achieve this.
Proficiency Testing (PT): This involves a laboratory's participation in a program where they receive samples with unknown characteristics. The laboratory performs tests on these samples and submits their results. These results are then compared to reference values or the results from other competent laboratories. Any discrepancies are evaluated to identify potential causes such as methodological errors or instrument calibration issues. PT helps laboratories assess and improve their testing accuracy and reliability.
Inter-Laboratory Comparisons: Similar to PT, inter-laboratory comparisons involve multiple laboratories conducting the same tests on identical samples. The results obtained from these different laboratories are compared to evaluate the degree of agreement between them. Consistency among the results indicates reliability in the testing methods and procedures used across these labs.
Compliance with Clause 7.7, including proficiency testing and inter-laboratory comparisons, is essential for laboratories seeking accreditation under ISO/IEC 17025:2017 to demonstrate their technical competency and the validity of their testing and calibration results.