Proficiency testing and ring trials.

Abstract

The validation of diagnostic methods (and the subsequent results generated by a laboratory) are improved through participation in inter-laboratory comparisons (IC), such as proficiency-testing (PT) programmes and other exercises referred to as 'ring tests' or 'ring trials' (RTs). This is a requirement to comply with international quality standards. Validating a method is a continuous process and taking part in ongoing PT programmes supports the management of a method's life cycle, providing continuing assessment of fitness (sometimes referred to as the 'validation retention status'). Proficiency-testing panel designs ensure that the methods used, particularly diagnostic specificity and sensitivity, are suitably challenged. Appraising PT results over time can illustrate whether the laboratory's performance is stable, improving or worsening, and proficiency tests can also highlight variations in the performance of assays. The development of new proficiency tests can support the implementation of novel diagnostics technologies, such as whole genome sequencing and point-of-care testing, and assist in cross-sectoral partnerships focusing on One Health approaches, which are high on the agenda for infectious disease control. For example, the rapid design and distribution of emergency exempted assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) means that these assays were not as rigorously evaluated as assays for established infectious diseases. Therefore, participation in PT programmes for SARS-CoV-2 is essential to understand the performance of these assays. While other mechanisms help to underpin laboratory activities, PT has been, and should remain, an integral part of laboratory quality assurance. Resources must be directed towards increasing and improving the quality of PT (for example, availability and accessibility of suitable biological and reference materials are essential for a PT provider to execute its duties), to support established and novel methods such as genomic and point-of-care tests.