Introduction
In laboratory quality assessment, Ring Trials (interlaboratory tests) and Proficiency Testing (competency tests) compare results among different laboratories. Both improve accuracy and reliability but have distinct objectives, methodologies, and applications.
Ring Trials harmonize and validate methods, while Proficiency Tests assess laboratory competence.
Ring Trials: Definition and Characteristics
A Ring Trial is an interlaboratory test where multiple laboratories analyze the same sample under controlled conditions following a standardized protocol. This key distinction sets it apart from Proficiency Testing, as the objectives differ.
While the Ring Trials are looking for evaluation of variability between laboratories to improve the reproducibility of analytical methods. They are common in method validation and harmonization studies, such as CEN/TC 216. Standardized conditions minimize external influences, ensuring accurate assessments of precision and robustness.
Conversely, Proficiency Testing evaluates a laboratory’s technical competence in specific analyses. Organizers provide concealed samples with known values. Results are then compared against reference values or those from other laboratories. Unlike Ring Trials, Proficiency Testing does not assess the method itself but how accurately a laboratory applies its procedures. This assessment is essential for accreditation, particularly under ISO/IEC 17025.
Key Differences Between Ring Trials and Proficiency Testing
The primary differences lie in their purpose and execution:
- Ring Trials assess method reproducibility, identifying variations to harmonize techniques.
- Proficiency Testing evaluates technical competence of the laboratory without requiring a standardized protocol.
In Ring Trials, reference values emerge from participant results, allowing variability analysis. Participating laboratories adhere to a single protocol to ensure comparability.
Meanwhile, in Proficiency Testing, each laboratory follows its routine processes. There is no unified protocol since the goal is to assess real-world performance. While Ring Trials support method validation and harmonization, Proficiency Testing ensures quality control and accreditation compliance.
Experimental Conditions
For both tests, sample homogeneity is crucial to ensure variations stem from methods rather than sample differences. However, experimental conditions differ significantly.
In Ring Trials, a standardized protocol minimizes differences among laboratories. All participants use identical reagents and equipment to evaluate method reproducibility. This uniformity helps identify factors influencing precision and accuracy, enabling procedural refinements.
In contrast, Proficiency Testing allows laboratories to operate under normal conditions. Each uses its usual methods, accepting variability as an expected outcome. The focus is not on a method but on evaluating the technical competence of the laboratory to obtain accurate results.
Ring Trials: Sample and Media Preparation
Sample and media preparation further differentiate these assessments.
In Ring Trials, a reference laboratory prepares and distributes samples. Some laboratories may prepare media themselves, following a common protocol. This standardization ensures comparability.
For Proficiency Testing, a Proficiency Testing Provider (PT provider) prepares and distributes samples with unknown values. Each laboratory prepares its own media and applies its standard procedures. No modifications are made, as the objective is to evaluate real-world performance to demonstrate the technical competence of the laboratory.
Comparative Table of Ring Trials and Proficiency Testing
| Target | Ring Trials (RT) | Proficiency Testing (PT) |
| Main Objective | Evaluation and validation of analytical methods. | Assessment of laboratory competence. |
| Reference Values | May be derived from participants’ results. | May be derived from participants’ results.
Pre-established and concealed from participants. |
| Frequency | Occasional, as needed for method validation. | Regular and periodic as part of quality control. |
| Operating Conditions | Standardized protocols to minimize methodological variations. | Each laboratory uses its own method, equipment, and reagents. |
| Participation | Voluntary, mainly used in method harmonization and development studies. | Mandatory for laboratory accreditation under international regulations. |
| Applicable Standards | Not always ISO-compliant. | Usually complies with ISO/IEC 17043 and ISO/IEC 17025. |
| Comparison Method | Comparison among laboratories to improve method reproducibility. | Comparison of laboratory performance to technical competence laboratory assessment. |
| Sample Preparation | A reference or organizing laboratory prepares and distributes the samples. | A specialized PT provider supplies samples with hidden values. |
| Primary Application | Development, validation, and harmonization of analytical methods. | Quality control and compliance with accreditation standards. |
| Methodological Flexibility | Requires adherence to a common protocol to ensure data comparability. | Allows each laboratory to use its standard methodology without specific adjustments. |
Importance of Participation in Interlaboratory Assessments
Regular participation in Proficiency Testing helps laboratories refine processes, identify improvement areas, and ensure internationally comparable results. Accreditation under ISO/IEC 17043 guarantees rigorous standards, ensuring objective evaluations.
Both Ring Trials and Proficiency Testing play critical roles in laboratory performance assessments. Ring Trials aid method harmonization, while Proficiency Testing verifies technical laboratory competence. However, we must keep in mind that Ring Trials alone cannot demonstrate technical competence.
Other assessments also contribute to laboratory quality assurance:
- Internal Quality Assurance (IQA): Internal evaluations comparing a laboratory’s own results over time. This method detects deviations but remains limited to internal data.
- External Quality Assurance (EQA): Laboratories receive samples from an external provider to evaluate routine test performance. Unlike Proficiency Testing, EQA may not always be fully blind.
- Interlaboratory Comparisons (ILC): Multiple laboratories analyze the same sample for comparative purposes. Not all ILCs assess competence; some focus on research and method development.
Each assessment serves a distinct purpose, chosen based on organizational objectives. SHAPYPRO supports laboratories in implementing these evaluations, ensuring impartiality and robust results.
Our 5-Year Agenda and Why Choose Us
At SHAPYPRO, we provide ISO/IEC 17043:2023-accredited proficiency testing programs, backed by a strategic growth plan focused on innovation and quality. Our 5-year agenda include:
Our service catalog reflects our commitment to excellence, offering customized solutions to meet laboratory needs. Get to know us and discover how we enhance analytical quality.
Why Choose SHAPYPRO?
At SHAPYPRO, we understand the critical role of quality and reliability in laboratory analysis. As the only ISO/IEC 17043:2023-accredited provider for biocides proficiency testing, we ensure maximum rigor and compliance with international standards.
We offer tailored solutions for Proficiency Testing, helping laboratories meet the highest accreditation standards. Our expertise in method optimization and quality control enhances performance and ensures result accuracy.
Contact us today to learn how we can help optimize your operations and guarantee reliable analyses.