Proficiency Testing

GCC Standardization Organization ‘GSO’ is committed to support Conformity Assessment Bodies in GSO member states and facilitate the access to technical services, such as Proficiency Testing Programs (PT), in order to enhance the level of competence and ensure reliable outcome of all bodies operating in the region. Periodically, GSO conducts surveys whose outcome is considered a relevant tool to identify accurately the need in term of Proficiency Testing Schemes and helps to settle clear targets for the upcoming programs as part of GSO strategic plan 2016 – 2020.

Related Quality Standards: ISO/IEC 17043 and ISO 13528

ISO/IEC 17043 has been prepared to provide a consistent basis for all interested parties to determine the competence of organizations that provide proficiency testing.

ISO 13528 provides support for the implementation of ISO/IEC 17043 particularly, on the requirements for the statistical design, validation of proficiency test items, review of results, and reporting summary statistics. This international standard is intended to be complementary to ISO/IEC 17043, providing detailed guidance that is lacking in that document on particular statistical methods for proficiency testing.

The definition of proficiency testing in ISO/IEC 17043 is adopted in ISO 13528, with a comprehensive description of different types of proficiency testing and the range of designs that can be used.

ISO 13528 incorporates published guidance for the proficiency testing of chemical analytical laboratories but additionally includes a wider range of procedures to permit use with valid measurement methods and qualitative identifications.

Use of Proficiency Testing results by interested parties

Accreditation Bodies : The requirements for an accreditation body with regard to use of proficiency testing are specified in ISO/IEC 17011 and ILAC P9. The results from proficiency testing schemes are useful for both participants and accreditation bodies. Successful performance in a specific proficiency testing scheme may represent evidence of competence for that exercise, but may not reflect ongoing competence. Similarly, unsuccessful performance in a specific proficiency testing scheme may reflect a random departure from a participant’s normal state of competence. It is for these reasons that proficiency testing should not be the only tool used by accreditation bodies in their accreditation processes.

For participants reporting unsatisfactory results, the accreditation bodies should have policies to:

  • ensure that the participants investigate and comment on their performance within an agreed time-frame, and take appropriate corrective action,
  • where necessary, ensure that the participants undertake any subsequent proficiency testing to confirm that any corrective actions taken by them are effective, and
  • where necessary, ensure that on-site evaluation of the participants is carried out by appropriate technical assessors to confirm that corrective actions are effective.

The accreditation bodies should advise their accredited bodies of the possible outcomes of unsatisfactory performance in a proficiency testing scheme. These may range from continuing accreditation subject to successful attention to corrective actions within agreed time-frames, temporary suspension of accreditation for the relevant tests, through to withdrawal of accreditation for the relevant tests.

Regulatory Bodies : The results from proficiency testing schemes are useful for regulatory bodies that need to evaluate the performance of participants covered by regulations. If the proficiency testing scheme is operated by a regulatory body, it should be operated in accordance with the requirements of ISO/IEC 17043.

Regulatory bodies that use independent proficiency testing providers should seek documentary evidence that the proficiency testing schemes comply with the requirements of ISO/IEC 17043 before recognizing the proficiency testing scheme, discuss with participants the scope and operational parameters of the proficiency testing scheme, in order that the participants’ performance may be judged adequately in relation to the regulations.

Selection of Proficiency Testing Schemes

Laboratories and other concerned bodies need to select proficiency testing schemes that are appropriate for their scope of testing or scope of calibration. The proficiency testing schemes selected should as much as possible comply with the requirements of ISO/IEC 17043.

In selecting a proficiency testing scheme, the following factors should be considered:

  • the tests, measurements or calibrations involved should match the types of tests, measurements or calibrations performed by the participant,
  • the availability to interested parties of details about the scheme design, procedures for establishment of assigned values, instructions to participants, statistical treatment of data, and the final summary report,
  • the frequency at which the proficiency testing scheme is operated,
  • the suitability of the organizational logistics for the proficiency testing scheme (e.g. timing, location, sample stability considerations, distribution arrangements,
  • the suitability of acceptance criteria,
  • the cost,
  • the proficiency testing provider’s policy on maintaining participants’ confidentiality,
  • the timescale for reporting of results and for analysis of performance data,

The characteristics that compromise confidence in the suitability of proficiency test items (e.g. homogeneity, stability, and, where appropriate, metrological traceability to national or international standards).

Closed Proficiency Testing (PT) Programs

Ongoing Proficiency Testing (PT) Programs

View our 2023 Catalog For Proficiency Testing (PT) Programs , and sign up for our PT programs:

Scope: Steel Bars

Scope: Steel Bars

Scope: Cement

Scope: Diesel Fuel

  • Testing Features: Determination of Flashpoint and Sulfur content in Diesel Fuel
  • Program Code: GSO-KTR PT/04/2023

Registration Link:


Useful documents and links


Products bearing the G-Mark registered by Gulf Notified Bodies.


Conformity Certificates and Fuel Efficiency Labels for Motor Vehicles, Motorcycles and Tyres.

Notification System

Designation of Conformity Assessment Bodies as Gulf, Bahrain & Oman Notified Bodies.



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