Basic instructions for participants in a proficiency testing scheme

Significance of the topic

Proficiency testing (PT) schemes play a critical role in analytical chemistry by benchmarking laboratory performance, ensuring method validity and supporting accreditation. Regular participation helps detect systematic errors, maintain confidence in results and enhance comparability across laboratories.

Objectives and Overview

This guide presents a practical checklist for laboratories engaging in PT schemes. It outlines the principal stages—pre-participation planning, receipt and handling of PT items, analytical measurements, result reporting, evaluation of performance and follow-up actions—aiming to minimize errors and optimize outcomes.

Methodology

The stepwise procedure comprises:

• Pre-participation: Confirm provider contacts and update billing/shipping details; establish documented procedures for result review, corrective actions, trend analysis and report archiving.
• Receipt of PT materials: Inspect packaging upon arrival; communicate with the provider to replace compromised samples; register, label and store items per provider instructions.
• Measurements: Follow provider protocols closely; conduct analyses under routine conditions unless otherwise directed; respect deadlines.
• Result reporting: Allocate sufficient time; submit all required information using correct units, significant figures and formats; verify data entry before final submission.
• Review of PT reports: Examine performance summaries promptly; confirm accurate representation of submitted results; note evaluative comments as context for performance.
• Follow-up: Investigate any unsatisfactory results through the quality management system; assess potential impact on past data; implement corrective actions; use surplus PT materials to verify improvements; track performance trends over time.

Main Findings and Discussion

The guide emphasizes that careful planning and adherence to standard procedures at each stage reduce common pitfalls such as sample misidentification, reporting errors or delays. Consistent documentation supports accreditation requirements and facilitates continuous improvement.

Benefits and Practical Applications

• Enhanced data reliability and traceability.
• Identification and correction of procedural weaknesses.
• Evidence of competence for accreditation bodies and customers.
• Opportunity to compare methods and benchmark performance.

Future Trends and Opportunities

Emerging digital platforms may streamline PT registration, data submission and report analysis. Integration of secure online portals with automated performance tracking and trend visualization tools will improve efficiency. Expansion of specialized PT schemes for novel analytes and advanced techniques (e.g. high-resolution mass spectrometry) is expected to address evolving industry needs.

Conclusion

Adopting a structured approach to proficiency testing strengthens laboratory quality systems and ensures credible analytical results. Systematic preparation, accurate execution and thorough review are essential to derive maximum benefit from PT participation.

References

1. B. Brookman and I. Mann (eds.), Eurachem Guide: Selection, Use and Interpretation of Proficiency Testing (PT) Schemes, 3rd ed., 2021.
2. Eurachem, Selecting the Right Proficiency Testing Scheme for My Laboratory, Ed.2, 2022.
3. Eurachem, Proficiency Testing – How Much, and How Often?, Ed.2, 2022.
4. Eurachem, How to Investigate Poor Performance in Proficiency Testing, Ed.2, 2022.
5. Eurachem, Use of Surplus Proficiency Test Items, Ed.2, 2022.