Technically speaking they are different but both Proficiency testing and Inter-laboratory comparisons serve a common objective – to validate test procedures adopted in a laboratory and build confidence amongst clients, auditors, accrediting and regulatory bodies on the competence of a laboratory’s capabilities to carry out a particular analysis and report results with highest degree of reliability.
Your laboratory may be equipped with latest state of art facilities and highly trained manpower but regular inter laboratory comparisons and proficiency testing programs help in assuring laboratory competence which is essential for a sustained growth. The two terms appear to convey the same meaning but are different and it is necessary to understand the fine difference between them.
Proficiency testing or round robin testing, as it is commonly referred to, involves testing the same sample in more than one laboratory for comparison of results. The results are collected and after statistical analysis a report is generated. The participating laboratories have no preliminary knowledge of the actual value but once the report is made available it helps them assess their competency to carry out such testing in terms of validity of adopted test method, adequacy of training of analysts, traceability of standards and reference materials and environmental controls existing in the laboratory. In other words proficiency testing ensures that all established norms and systems in the laboratory are in force up to the required compliance levels specified by regulatory bodies.
Participation in proficiency testing is an essential requirement for calibration laboratories seeking accreditation under ISO 17025: 2005. A calibration laboratory aspiring for accreditation must have participated in one proficiency test prior to its application and post accreditation it is required to participate in one proficiency test for each major discipline such as chemical, biological or mechanical every four years.
Inter laboratory comparisons help establish the fact that a laboratory is capable of providing results of high degree of accuracy to its clients and also to validate that the method adopted is fit for its intended purpose.
Inter laboratory comparisons serve several important criteria of laboratory testing:
- Validation of new or existing methods of analysis
- Help resolve differences in correct interpretation and implementation of test methods between participating laboratories
- Provide solutions to existing problems and offer remedial measures
- Boost morale of laboratory chemists and at same time add to client confidence in testing services offered by a laboratory.
In conclusion it can be said that proficiency testing and inter laboratory comparisons are not meant to create rivalries between participating laboratories but if taken in the right spirit pave a way for increased technical collaboration for validation of test methods and evolve industry specific reference materials.