Proficiency Testing (PT) is one of the cornerstones of a well defined laboratory quality management system. In addition to the internal quality controls performed daily, PT provides a powerful tool allowing comparisons with similar laboratories in order to verify the accuracy and reliability of their test results.
The purpose of PT is not just passing the test but moving towards continued quality improvement in the laboratory. One of the major benefits of PT is to provide an external tool for identifying performance issues and taking remedial action before they become erroneous patient test results. Another benefit is enabling laboratories to monitor their tests over time. Longer-term trends can be identified, and any necessary corrective action implemented.
Laboratories in the province are required to participate in PT and Alternative PT programs that reflect their range of accredited services. The DAP will mandate or recommend certain programs and monitor individual laboratory performance for these.
The DAP maintains its own records of laboratory PT performance, including the outcomes of investigations and subsequent corrective actions. PT performance history will be a factor considered when determining the overall Accreditation Award.
A PT program is a quality assessment tool that provides a retrospective measure of technical quality. To be most effective, PT must be used in conjunction with the laboratory’s internal quality control program and be a part of the quality management system.
The objectives of the PT program for the Diagnostic Accreditation Program are to:
- determine the ability of individual laboratories to perform tests competently
determine performance by individual laboratories for specific tests and monitor continuing performance
identify problems that indicate true poor performance and initiate remedial action
identify inter-laboratory differences
determine the performance characteristics of specific analytical systems
compliment the information gained from on-site peer review visits and other accreditation program activities that assess quality, competency and compliance with standards
provide opportunities for education
Limitations of Proficiency Testing
According to the Clinical and Laboratory Standards Institute: GP27-A: Using Proficiency Testing (PT) to Improve the Clinical Laboratory; Approved Guideline “It is important to bear in mind the limitation of proficiency testing. It addresses only the analytic process, not the pre- or post-analytic activities of the laboratory. Proficiency testing results are affected by variables not related to patient testing, including preparation of the proficiency sample, matrix effects, clerical function, selection of statistical methods of evaluation, and peer group definition. Accordingly, it is not appropriate to use proficiency testing as the sole means for evaluating the quality of a laboratory.”
Exception Response – Action and Feedback
Laboratories are required to investigate and comment on unacceptable performance in writing, to the DAP within a designated time-frame. Corrective actions that are initiated by the laboratory require monitoring to ensure they are effective.