Proficiency Testing organization

A number of international organizations are active in the field of clinical chemistry reference materials and proficiency testing, these include ... 

The principle of proficiency testing schemes consists in analyzing one or more samples sent to the laboratories by an external body. The analytical results returned to the organizer are evaluated in comparison to the assigned value(s) of the sample(s). 

Organizations whose measurement results are with 25% of the known exposure level will be considered to have met the proficiency test requirements. 

There are numerous proficiency testing schemes available, operated by a number of different organizations, Table 7.1 gives some examples. Further information on the range of proficiency testing schemes available can be found on EPTIS, a web-based Proficiency Testing information system. This is a database of PT schemes covering most measurement sectors (www.eptis.bam.de). 

Table 7.1 Examples of proficiency testing schemes organized by UK providers...

Irrespective of the type of proficiency testing scheme, it is usually organized in a sequence of clear steps. 

Proficiency Testing by Interlaboratory Comparisons - Part 1 Development and Operation of Proficiency Testing Schemes , ISO/IEC Guide 43-1 1997, International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC), Geneva, Switzerland, 1997. 

Participance in Proficiency Testing Schemes Proficiency testing (PT) is the periodic assessment of the competency or the analytical performance of individual participating laboratories [23]. An independent coordinator distributes individual test portions of a typical uniform test material. The participating laboratories analyze the materials by their method of choice and return the results to the coordinator. Test results obtained by different laboratories are subsequently compared with each other and the performance of each participant evaluated based on a single competency score [64,107]. International harmonized protocols exist for the organization of PT schemes [59,60,64,69,79]. 

The test material is chosen to fulfill the aims of the study. In a proficiency testing scheme or a method validation study, the test material is usually as near as possible to typical field samples. There is no advantage in competently analyzing an artificial sample if the same laboratory has difficulty with real samples. The organizing laboratory must know the composition of the test material, and must be sure that the analyte for which a quantity is to be measured is present in about the desired amount. For pure materials this is not a problem, but for natural test materials or complex matrix materials, the organizing laboratory may have to do some analyses before the samples can be sent out to the participants. If the value of the measurand is to be established by an independent laboratory before the study, then the identity requirement is also fulfilled when the measurand is stated. 

ISO/IEC (1997), Proficiency testing by interlaboratory comparisons—Part 1 Development and operation of proficiency testing schemes, Guide 43 (Geneva International Organization for Standardization). 

Some important assays commonly used in biochemical genetics laboratories do not provide quantitative data (e.g. MPS-EP, qualitative urinary organic acid analysis, AA-TLC). In addition, all successful investigations depend heavily upon selection of the correct analytes to measure and the appropriate interpretation of the quantitative or qualitative results in their clinical context. These challenges suggest a requirement for external quality assessment or proficiency testing schemes that can inform participants about their performance in these areas when compared with other centres. 

ISO/IEC 43-1 1997 Proficiency testing by interlaboratory comparisons - Part 1. Development and operations and proficiency testing schemes. International Organization for Standardization (ISO), 1, Rue de Varentie, Case Postals 56, CH-2111 Geneva 20, Switzerland... 

INPL participates in the Brewing Analytes Proficiency Testing Scheme (BAPS) organized by the Laboratory of the Government Chemist (LGC) in the United Kingdom. So, once a month INPL analysts (co-authors of the present article B. Anisimov and I. Goldfeld) perform etha-... 

Standard Operating Procedure for the Organization of OPCW Proficiency Tests , QDOC/ LAB/SOP/PROOO1 (6) ... 

Matrices most used were soil, water, and organic liquids. Other matrices used were, for example, a polymer strip in the first proficiency test, a metal strip covered with a thin layer of paint in the third proficiency test, and a wipe sample in the fourth proficiency test. In the ninth and tenth proficiency tests, an emulsion sample and decontamination solutions were introduced. Not all sample matrices employed in the past are considered realistic. During the Preparatory Commission of the OPCW, the Task Force on Analytical Issues (see Fourth Report of the Expert Group on Inspection Procedures, PC-VIII/B/WP.12, dated September 20, 1994) discussed that sample matrices such as wipe, rubber, paint, and concrete will be extracted on site and sent as extracts off site for analysis, after splitting. 

One of the samples in the eighth proficiency test was an organic liquid sample with dichloromethane (CH2C12) as solvent. The sample was spiked with ... 

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