KAN-G-03 - KAN Guide on Conducting Proficiency Testing

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Issue Number : 4 April 2016

Komite Akreditasi Nasional

National Accreditation Body of Indonesia Gedung I BPPT, Lt. 14

Jl. MH Thamrin No. 8, Kebon Sirih, Jakarta 10340 – Indonesia Tel. : 62 21 3927422 ext 173, 194, 195, 197, 210, 211 Fax. : 62 21 3927528

Email : laboratorium@bsn.go.id Website : http//:www.kan.or.id


KAN-G-03 Issue Number : 4 April 2016


Reviewed by :

Quality Manager

Approved by:

Director for Accreditation of Laboratory and Inspection Body


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No. Date Part number

revised Brief description of changes


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KAN conducts annual proficiency testing program for both testing and calibration laboratories. Proficiency testing program conducted by KAN is a program for comodities outside the scope of Proficiency Testing Provider (PTP) which has been accredited by KAN. Due to the big variety on scope of testing and calibration, the selection of program is carried out based on the following criteria but not limited to:

 Be the accreditation scope possessed by relatively big number of laboratories;and/or

 Be the accreditation scope that significantly contribute directly or indirectly to the main Indonesian export commodities (products);and/or

 Be supposed to be carrying out of obligatory national standard(SNI)

 Outside the scope of Proficiency Testing Provider which has been accredited by KAN.

In addition, KAN also actively participate in other proficiency testing activities coordinated by regional, or international bodies.


In executing proficiency testing program, KAN may form Proficiency Testing Expert Group (PTEG). The main task of the PTEG is to plan, including preparation of proficiency testing protocol, to carry out and to evaluate the results. Criteria of being member of PTEG are as follows:

 be competent in the relevant field of testing, and/or calibration;

 have appropriate knowledge on proficiency testing, particularly in relation to the understanding of ISO/IEC 17043 and ISO 13528.


KAN may appoint sample/artifact provider to prepare the test sample and/or artifact for the need of proficiency testing. Criteria of sample/artifact provider for being appointed is as the following:

 an accredited laboratory for testing, calibration or, if relevant National Measurement Institute (NMI) for calibration; and


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Participants of KAN Proficiency Testing Program are mainly accredited testing, and calibration laboratories. Non accredited laboratories may also participate in KAN Proficiency Testing Program regardless their status as far as they follow KAN rule and procedure on Proficiency Testing.


As for KAN’s assessment activities, all information supplied by participants are treated as confidential. This information will, however, be made available to the assessor(s) of laboratory, the PTEG and KAN technical committee. All of these people are fully aware of confidentiality of the results.


The current policy is to levy each participant in aprogram with a fee that contributes to the cost for conducting that program. The varies from program to program and participants are notified accordingly prior to commencement the program.


7.1 Introduction

Most of interlaboratory comparisons conducted by KAN are subdivided samples (taken from a bulk sample) that are distributed to participating laboratories which test them concurrently. They then return results to KAN for analysis.

7.2 Working Group and Program Design

KAN proficiency testing is carried out annually. The program for each year is selected by KAN PT at the beginning of the respective year.

The preparation of program includes :

 nomination of tests to be conducted, range of values to be included, test methods to be used and number/ design of samples required;

 preparation of paperwork (instructions and results sheet) particularly with reference to reporting formats, number of significant figures/decimal places to which results should be reported and correct units for reporting;


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 An appropriate statistical design is essential and therefore must be established

during the preliminary stages of the program based on ISO 13528.

7.3 Documentation

The main documents associated with the initial phase of a proficiency program are:

(a) Letter of Intent

This is sent to prospective participants, including all accredited and applicant laboratories to advise that the program will be conducted and provides information on the type of samples and tests which will be included, the schedule and participation fees.

(b) Instructions to Participants

These are carefully designed for each individual program and participants are always asked to adhere closely to them.

(c) Results Sheet

For most program, results sheet is supplied to enable consistency in the statistical treatment of results.

Instructions and results sheets may be issued with or prior to the dispatch of samples.

7.4 Packaging and Dispatch of Samples

The packaging and method of transport of the samples are considered carefully to ensure that they are adequate and able to protect the stability and characteristics of the samples. Certain restrictions on transport such as dangerous goods regulations or customs requirements are complied with.

7.5 Receipt




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7.6 Analysis of Data and Reporting of results

Results are usually analysed together (with necessary distinctions made for method variation) to give consensus values for the entire group. The results received from participating laboratories are entered and analysed as soon as practicable so that an interim report can be issued to participants within two to four weeks of the due date for results.

This letter includes preliminary feedback including the consensus values for each test/sample and also features of the program’s design. Laboratories reporting one or more result(s) that are significantly different from the consensus values are encouraged to commence investigative/corrective action prior to the release of the final report.

The evaluation of the results i s described in ISO 13528.

A final report is produced at the completion of a program and includes data on the distribution of results from all laboratories, together with an indication of each participant’s performance. This report typically contains the following information:

(a) introduction

(b) features of the program - number of participants, sample description, tests to be carried out

(c) results from participants

(d) statistical analysis, including graphical displays and data summaries (e) a table summarising the extremed results

(f) technical comments (on possible causes of extreme results, method effects overall performance etc.)

(g) sample preparation and homogeneity testing information (h) a copy of the instructions to participants and results sheet

7.7 Follow-up of PT Results


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8. Calibration Interlaboratory Comparisons

8.1 Introduction

Each accredited calibration laboratory has its accredited capability uniquely expressed both in terms of its ranges of measurements and uncertainty applicable in each range. Because calibration laboratories are generally working to different levels of accuracy it is not normally practicable to compare results on a group basis such as in interlaboratory testing programs. For calibration programs we need to determine each individual laboratory’s ability to achieve the level of accuracy for which they are accredited (their least uncertainties of measurement).

The assigned (reference) values for a calibration program are not derived from a statistical analysis of the group’s results. Instead they are provided by a Reference Laboratory which must have a higher accuracy than that of the participating laboratories. For KAN interlaboratory comparisons the Reference Laboratory is usually the Puslit Metrologi LIPI, which maintains Indonesia’s primary standards of measurement.

Another difference between calibration and testing programs is that there is usually only one test item (known as an artefact) which has to be distributed sequentially around the participating laboratories, making these programs substantially longer to run. Consequently, great care has to be taken to ensure the measurement stability of the artefact.

8.2 Program Design

Once a program has been selected, a small working group maybe formed. This group usually comprises one or more technical advisers from Puslit Metrologi LIPI as NMI and KAN proficiency testing officer who will act as the program coordinator. The group decides on the measurements to be conducted, how often the artefact will need to be recalibrated and the range of values to be measured. They also formulate instructions and results sheets. KAN’s program are designed so that it will normally take no more than one year for each program.

8.3 Artefact Selection


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A Letter of Intent is sent to all accredited and applicant laboratories to advise that the program will be conducted and to provide as much information as possible.

Instructions to Participants are carefully designed for each individual program and it is essential to the success of the program that the participating laboratories adhere closely to them.

Results Sheet is used, to ensure that laboratories supply all the necessary information in a readily accessible format.

8.5 Artefact Stability

The artefact is distributed sequentially around the participating laboratories. To ensure its stability it is usually calibrated at least at the start and at the end of the circulation. For artefacts whose values may drift during the course of the program (e.g. resistors, electronic devices, etc.) more frequent calibrations and checks are necessary.

8.6 Evaluation of Performance

As stated in Section 8.1, calibration laboratories are generally working to different levels of accuracy. Consequently, their performance is not judged by comparing their results with those of the other laboratories in an intercomparison. Instead, their results are compared only to the Reference Laboratory’s results and their ability to achieve the accuracy for which they are accredited is evaluated by calculating the En as described in ISO 13528.

8.7 Reference Values

Puslit Metrologi LIPI provides most of the reference values for KAN interlaboratory comparisons. The majority of the participating laboratories’ reference equipment is also calibrated by Puslit Metrologi LIPI. As stated previously, it is important to select an artefact with high resolution, good repeatability and good stability. This is to ensure that these factors do not contribute significantly to the reference value uncertainty. Likewise, the Reference Laboratory must have the capability to assign uncertainties of measurement that are better than the participating laboratories. Otherwise it will be more difficult to evaluate each laboratory’s performance.


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derived from the mean of the Reference Laboratory calibrations carried out before and after the measurements made by the participating laboratories. Where a step change is suspected, then the reference values will be derived from the most appropriate Reference Laboratory calibration.

Where an artefact is calibrated a number of times during an intercomparison, participants’ results can be graphed using the difference between each laboratory’s result and the appropriate reference value (LAB– REF), rather than the actual laboratory results and corresponding reference values. This also helps maintain the confidentiality of the reference values for later use of the artefact.

8.8 Uncertainty of Measurement

To be able to adequately intercompare laboratories they must report their uncertainties with the same confidence level. A confidence level of 95% is the most commonly used internationally. Laboratories should also use the same procedures to estimate their uncertainties as given in the ISO Guide 98 Series (GUM), which has been adopted by laboratory it specific field.

Laboratories should not report uncertainties smaller than their accredited uncertainty of measurement.

8.9 Reporting

Whenever practicable an Interim Report is sent to laboratories to give them early feedback on their performance. The interim report states the En values for each measurement based on the preliminary reference values and usually does not contain any technical commentary.

A Final Report is sent to the Authorised Representative of each laboratory at the conclusion of the program. This typically contains more information than is provided in the interim report - including all participant’s results and uncertainties, final En numbers, technical commentary and graphical displays.

8.10 Corrective Action

Where a laboratory reports results which are deemed unsatisfactory, the laboratory will be notified and asked to check their results and provide an explanation. If it is a measurement problem then every effort will be made to arrange a re-calibrate of the artefact. The reference values will not be released to the laboratory until after the retest results have been received, however, they may be given an indication of which results require attention and whether they are consistently higher or lower than the reference values.


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P 06 will then be considered in conjunction with the Technical Adviser and the Field Manager.

Where suitable artefacts exist, these audits are mandatory for calibration laboratories applying for accreditation or significantly extending their scope of accreditation. They may also be employed for the evaluation of proposed KAN signatories or where laboratories due for reassessment have not recently participated in a proficiency testing activity in a particular area.

Normally, the artefact(s) will be sent to a laboratory prior to an assessment so that the resulting information is available to the assessment team. In some cases the measurement audit (or part of it) is witnessed by the assessment team, for instance, when a proposed signatory is carrying out the measurement.

Procedures are the same as for a normal interlaboratory comparison except that usually only a simple report is generated. In some cases the laboratories may only be told that they are within their uncertainty of the reference value.

If problems arise the laboratory is given the chance to retest, but subsequent poor performance would preclude granting of accreditation for specific calibration area.


1. ISO/IEC 17043, Conformity Assessment – General Requirements for proficiency Testing Provider

2. ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

3. ISO 13528, Statistical methods for use in proficiency testing by interlaboratory comparison