For many labs, the answer seems straightforward: once a year, or whenever accreditation requires it. Participation often becomes part of the annual quality calendar. However, PT serves a broader purpose than simply fulfilling a periodic requirement. When planned thoughtfully, it helps labs monitor analytical performance, evaluate competence, and maintain confidence in the results they report. Guidance from ISO/IEC 17025:2017, NABL 163, and international discussions on PT participation encourage labs to look beyond fixed schedules and consider a risk-based approach to participation. When labs review PT participation from a practical perspective, following considerations usually shape the decision: Compliance, control, competence, cost, and the level of risk associated with the testing activity.
Participation in PT is an important element in demonstrating competence under ISO/IEC 17025:2017. Clause 7.7: Ensuring the validity of results requires labs to monitor the reliability of their results through activities such as proficiency testing, interlaboratory comparisons, or other appropriate quality control measures.
Similarly, NABL 163 recommends that labs participate in PT programs relevant to their accredited scope wherever such programs are available.
The expectation, however, is not participation merely for documentation. Labs are expected to show that their PT participation is planned, relevant to the scope of testing, and useful in monitoring performance.
From a lab’s operational perspective, PT also provides an external reference point for evaluating analytical performance.
When PT participation reflects the lab’s routine testing activity, it becomes an effective way to maintain control over testing performance.
PT participation also plays a role in evaluating analyst competence and method performance.
Additional participation may be useful when:
In such situations, PT provides reassurance that both the method and the analyst are capable of producing reliable results under routine testing conditions
Another important aspect of PT planning is ensuring that participation reflects the scope of the lab. Rather than selecting PT rounds randomly, labs may plan participation so that key parameters, matrices, and testing areas within the scope are represented over time. This approach provides a clearer and meaningful view of laboratory competence.
International discussions on PT increasingly support risk-based participation planning. Factors that labs may consider include:
Cost is naturally one of the considerations when labs plan PT participation. However, when participation is aligned with testing frequency, parameter risk, and performance monitoring needs, labs often find that PT becomes more purposeful.
Instead of participating in multiple unrelated schemes, labs can focus on programs that best represent their testing scope and quality objectives.
At Envirocare Labs Proficiency Testing, our objective is not only to conduct PT programs but also to support labs in planning participation in a way that strengthens their quality systems.
If your laboratory is reviewing its PT participation plan or exploring PT programs relevant to its testing scope, our team would be happy to guide you.
Dr. Priti Amritkar Director – Labs | Envirocare Labs In the intricate and high-stakes world…
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