Proficiency Testing/ Inter-laboratory Comparison

Independent proficiency tests are an important tool for laboratories to show evidence of their performance and to ensure that their test results can be trusted. Participating in independent proficiency tests is a critical check to verify the performance of laboratories. It is a mandatory requirement for the laboratories’ accreditation according to the ISO 17025 standard. When implementing quality systems, analytical laboratories must also prove their measurement capability. Proficiency Testing is a key element in the laboratory accreditation process, enabling labs to monitor the quality of their test results. Proficiency testing determines the performance of individual laboratories for specific tests or measurements, and is used to evaluate laboratories’ continuing performance. PT is also called interlaboratory comparison.
For labs who are pursing formal laboratory accreditation for the first time, it is particularly important as an initial step in that process and require successful demonstrated performance in PT programs prior to initial assessment. Even if there are no plans for accreditation, successful participation in PT programs can provide a handy means for demonstrating accurate laboratory performance, and be utilized in a variety of ways, from providing marketing materials for sales to measuring individual employee performance and training. The mechanics of a PT program are straightforward – an unknown sample(s) is received and analyzed by the laboratory, the lab results are returned to the PT provider, a statistical analysis of the all labs’ results is performed, and the individual laboratory receives data on their performance compared to all other laboratories (individual laboratory results are revealed only to each laboratory).