Purpose:
The purpose of the Procedure is to ensure that all EQA programmes designed by Thistle QA are handled in an effective and consistent manner, and one that ensures that each EQA satisfies the needs of both the participating laboratories and the organisational needs of Thistle QA.

Scope:
This procedure applies to all Industrial EQA programmes designed by Thistle QA, whether in response to a perceived market need, after a direct request, or in response to the results of a survey. Industrial laboratories will be considered for participation in the programmes listed inter-alia below.

Type 1 (CRM Based)
In this type of test Thistle QA will source certified reference materials from a commercial supplier suitable for analysis by the clients’ analytical methodology where a number of elements have well established values. The results of analysis carried out on these materials over an agreed review period will be evaluated by a number of statistical procedures and the performance of the laboratory assessed by the proximity to the certified value (“z” score) and the reproducibility of the test results (“t” test).
Type 2 (Specification Testing)
Certain products need to meet a given specification to be acceptable in the market or to meet a particular quality parameter e.g. impurities must lie within a specified range. Special High Grade (SHG) zinc is an example of such a commodity. Thistle QA will design an individual test programme and carry out statistical analysis of data produced by a laboratory to demonstrate that minor elemental components in current production batches are part of the same data set as those of the standard selected by the client and whose values are known to be acceptable by consensus.
Type 3 (Inter-laboratory Testing)
With the permission of individual laboratories and when sufficient participants’ results become available tables will be published comparing individual laboratory performance with that of the other participants for benchmarking purposes. In publishing these data individual laboratories are not identified other than by a code number known only to the laboratory concerned and Thistle QA
Type 4 (Method Validation)
Analysis of a material of known composition, not only of the major components but also those components which are not typically analysed for, is valuable in providing data for use in correcting for interferences in instruments with multi element capability. Once this data have been verified by proficiency testing the applicability of various analytical strategies can be compared. An example might be to compare results obtained using the high speed capability of multi-element XRF analysis when compared with those obtained from ICP instruments involving extended sample preparation times.
Type 5 (QA Report Validation)
Should a laboratory already operate a thorough and comprehensive QC system that complies with good quality management practices Thistle QA will review the data generated and issue a quality audit report based on verification of the conclusions drawn. It is our experience that such independent verification of results produced is a valuable marketing tool in a highly competitive environment.

Responsibility:
It is the responsibility of the Director or his designated deputy to initiate the investigation of a potential new EQA client as well as to maintain records of the design and evaluation of such EQA programmes after consultation with the client., This process serves to ensure that EQA programmes are completed in a manner compatible with the Purpose stated above.

Procedure:
Requirements regarding the need for a new EQA from Thistle QA may originate from either current or potential customers and from a number of sources. Alternatively, an EQA operating elsewhere may be presented to our participants in the form of a questionnaire or survey. The requirement will be discussed during a Management Review where future steps will be decided. If it is decided to proceed with the potential EQA, a file will be opened with specific information relating to the planned EQA. Items to be addressed will include some or all of the following:

1. Sample source: type of material, stability, price.
2. Availability methodologies:
   • which methods are applicable
   • will they give consistent results
   • are there widely accepted reference values?
3. Potential numbers of participants, with regard to validity of consensus data.
4. Transportation, any special requirements?
5. What instructions will participants need?
6. Frequency of sampling
7. What stats will be necessary
8. Dates of analysis and start date of EQA
9. Report format/validation of in-house reports using client data
10. Any published acceptable variation?
11. Any expert opinion required or available?

Once an EQA has been designed and started, it becomes subject to the usual control mechanisms of all Thistle QA schemes, such as Production Controls and Complaints Procedures.

Requests to add additional tests to an existing EQA will be considered by the Director and/ or Manager during a Management Review. The question of whether or not to accept the addition will be subject to the relevant sections in 2 a) through k).