Proficiency-testing reports

Within two weeks of the study closing date, we issue an interim report, the purpose of which is to provide rapid feedback to participants. At the conclusion of each study, a detailed final report is prepared and issued to participants. This report contains a full description of the study together with statistical analysis and graphical presentation of the results. The report is prepared in a standardised format consistent with ISO and ILAC guidelines for proficiency test reports. 

Figure 2. OPCW proficiency test report structure...

Analytical Methods Committee, Handling false negatives, false positives and reporting limits in analytical proficiency tests. Analyst, 122, 495, 1997. 

It must be remarked that terminology is not consistent and there are many widely used synon)ms. Quality control in this Chapter refers to practices best described as internal quality control. Quahty assessment is often referred to as external quality control, proficiency testing, interlaboratory comparisons, round robins or other terms. Internal Quality Control and External Quality Assessment are preferred because they best describe the objectives for which the RMs are being used, i.e. the immediate and active control of the results being reported from an analytical run or event, and an objective, retrospective assessment of the quality of those results. 

Although the providers of proficiency testing schemes should have a quality management system in place, on occasions problems can arise which will affect the quality of the data evaluation being carried out. These can include transcription errors during data entry, mistakes in the report, software problems and inappropriate criteria for evaluation being used. Such problems should be remedied by the provider once the problem has been identified. 

When the proficiency test is finished the PT provider has to report the results to the participants. This should be done as soon as possible, i.e. normally not later than 1 month after the deadline for the return of the analytical results, to give a quick feedback to the participants. This enables the laboratories to react and take corrective actions. To maintain confidentiality, only a code should be used to identify the laboratory in the report. 

Public reports about poor performance of a laboratory in a proficiency test could be the economic ruin of this laboratory... 

Proficiency tests first of all should help the laboratories improve their performance. But often they are also used as a control tool for accreditation bodies, customers and authorities. Thus, there may be a tendency among some participants to try to report a better performance than is justified. 

Participation in proficiency tests is not a prerequisite or an absolute substitute for IQC measures or vice versa. However, participance in proficiency tests is meaningless without a well-developed IQC system. IQC underlies participance in PT schemes, while IQC and participance in PT schemes are both important substitutes of AQA (Figure 6). It is shown that laboratories with the strongest QC procedures score significantly better in PT schemes [8,50]. Participance in PT can to a certain extent improve the laboratory s performance however unsatisfactory performance in schemes (up to 30% of all participants) has been reported. This means that there... 

The method of analysis is either prescribed, when this is regulated by law, for example, or the choice is left to the participant. In the latter case the method is reported with the result. In keeping with the aims of a proficiency testing scheme, the method used should be the routine method employed by the laboratory, and not some enhanced protocol designed to improve performance in the scheme. 

The diagnostic proficiency testing schemes offer the additional feature of test selection. Participants are provided with brief clinical details and are required to select the investigations to undertake and when completed, report their findings. 

Handling False Negatives, False Positives and Reporting Limits in Analytical Proficiency Tests , Analyst Cambridge, 1997, 122, 495. 

Evaluations of various soil and sediment samplers have been reported [56, 57]. The sediment shovel proved highly practical, but was limited because small particles tend to be lost when the shovel is lifted [56]. A cryogenic sediment sampler was less convenient to use, but allowed the collection of almost undisturbed samples. Houba described a different device for the automatic subsampling of soil, sediment and plant material for proficiency testing [57]. In another study, Thoms showed that freeze-sampling collects representative sediment samples, whereas grab-sampling introduces a bias into the textural composition of the 120 mesh fraction, due to washout and elutriation of the finer fractions [58]. 

The Occupational Safety and Health Standards (29 CFR 1910.1025 [2005]) require employers to collect biomonitoring samples from workers who have been exposed to airborne lead above the current action level of 30 pg/m3. Employers must have the samples analyzed by laboratories that have met OSHA requirements for blood lead proficiency testing. State health departments often require that increased blood lead results be reported (OSHA 2005). 

The proficiency test requires detailed reporting of the analysis results the reporting requirements are specified in the quality system document QDOC/LAB/WI/PRO003 (8), made available to all test participants. 

The proficiency test timeline is 15 calendar days upon receipt of the samples the test period is based on Paragraph 62 of Part II of the Verification Annex of the CWC, stipulating that the final inspection report must be completed within 30 days after the inspection. 

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. 

Only chemicals that are considered relevant within the scenario of the proficiency test are to be reported to avoid irrelevant chemicals being reported, in real off-site sample analysis, confidential information on the facility under inspection is revealed (e.g. information on an industrial production process that is not relevant to the implementation of the CWC). This requirement is a consequence of Paragraph C.17 of the Confidentiality Annex of the CWC, l1. The reporting of irrelevant chemicals is penalized with immediate failure of the test see Section 6.1. 

Figure 3. Model for proficiency test analysis and reporting strategy...

The model for an analysis and reporting strategy presented emphasizes the importance of a structured plan of work in combination with team s commitment, in the attempt to complete participation in the OPCW proficiency-testing scheme successfully. However, teamwork among laboratory staff may not be enough successful participation requires full support from management too. After all, management must understand that participation requires full devotion from the laboratory other tasks preferably have to wait for a later point in time. 

Figure 16. Overview of irrelevant and false positive chemicals, reported by participants in proficiency tests 1-10...

Lewisite 1 was used for spiking in the sixth and in the ninth proficiency test. The participants that failed to identify lewisite 1 did not describe an effective lewisite 1 sample preparation procedure (12) in their analysis report, which could indicate that no such procedure had been employed. The participants performances in the identification of lewisite 1 are summarized in Table 3. 

Methylphosphonic acid was used for spiking in the fifth and in the tenth proficiency test. Many participants, in particular, failed to identify methylphosphonic acid in the tenth test for reasons that are difficult to trace from their analysis reports. It can only be speculated that the high concentration of salt ( %% NaCl) in the sample has been the cause most of these participants did not describe an effective sample preparation procedure (e.g. cation exchange) for the removal of salts, and employed GC/MS as an indirect analysis technique. Indirect GC/MS analysis of methylphosphonic acid requires derivatiza-tion salts are known to influence the derivatization reaction negatively. The participants performances in the identification of methylphosphonic acid are summarized in Table 6. 

There is one element within the proficiency test process that causes difficulties for many of the participants. The proficiency-testing scheme trains participants to not report chemicals that are considered irrelevant within the scenario of the test and which, in real off-site analysis, could reveal confidential information that is considered not relevant in the context of the CWC. A review on how the test scenarios were applied revealed that participants are not really in a position to judge the relevancy of chemicals. It rather should be the Technical Secretariat making a final decision on the relevancy of chemicals instead, and, for that reason, accept the reporting of any chemical given that it is a degradation product of a Scheduled chemical or directly related to a Scheduled chemical. 

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