LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue
About Driving Quality Together
How can I measure my laboratory’s performance over time?
What could be the cause of my poor performance? A single poor result is not indicative of overall laboratory performance but neither is a single good result. Ideally, PT results should be monitored over time to detect potential bias or repeated unsatisfactory results. There are many possible reasons for a single poor result. It is therefore important to interpret the results from PT schemes within the context of an all- round quality assurance programme, including internal quality control, use of validated methods and reference materials. There are numerous potential causes of poor performance in a PT scheme which may include analytical and non-analytical errors. Analytical errors • Calibration / instrument problems • Extraction / clean-up • Interferences / matrix effects • Diagnostic kits / reagents • Analyst / method performance Non-analytical errors
You can do this by trend analysis. A single result simply reflects the performance of the laboratory on the particular day that the test was carried out and therefore gives limited information. Frequent participation in PT schemes over time can give greater insight into long-term performance and can help identify where internal bias may be occurring. One of the best methods of summarising performance scores over time is graphically as this gives a clear overview and is less prone to misinterpretation than numerical methods. Participants are therefore advised to monitor their PT results over time. An online trend analysis tool is included in the cost of your PT participation with AXIO Proficiency Testing. The online tool is built into the PORTAL reporting system and allows you to quickly plot your results over a range of rounds and easily download the charts for further circulation. More information regarding interpretation and trend analysis of proficiency testing results is given in the Eurachem guide on ‘Selection, Use and Interpretation of Proficiency Testing (PT) Schemes’ (available at www. eurachem. org) and ISO 13528. How can I receive advice and feedback? Communication with participants will be carried out through PT scheme-related documentation, emails, letters, or through local LGC offices. Open meetings may also be organised and all interested parties invited to attend. How can I send feedback? Comments on any aspect of our products and services are welcome either by phone, letter, email or by contacting your local LGC office.
• Calculation / transcription • Reporting format / units • Poor / incorrect storage • Test material defects
Test materials are subjected to rigorous quality control testing before being distributed to participants, and are unlikely to be the cause of a poor performance score. All possible reasons for a poor performance should be investigated fully in order to identify the most likely cause and to enable action to be taken to prevent recurrence. Repeat test materials are available after every distribution, but it is most important to investigate and understand the reason(s) for the failure, document this fully, and carry out corrective actions before repeating a test.
Can I suggest a PT scheme or test material? We welcome suggestions any time. Please complete the ‘Wish list’ form on our website: lgcstandards.com/AXIO
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