SA Quality for Metrology is a Proficiency Testing Provider accredited by the Italian body Accredia, according to ISO/IEC 17043:2010 standards (PTP Accreditation Certificate No. 0024P). According to EA, IAF and ILAC Mutual Recognition Agreements, this accreditation enables us to organize Interlaboratory Comparisons at an international level.

What is an Interlaboratory Comparison?

An Interlaboratory Comparison (ILC), also known as Proficiency Testing (PT), involves evaluating the performance of a laboratory by comparing it with other laboratories, as defined by ISO/IEC 17043 standards.

An ILC is conducted by organizing a circuit (round-robin test), in which the calibrations performed by participating laboratories on the same sample (measurement standard) are statistically compared with the results obtained by a reference laboratory using the same sample.

According to ISO/IEC 17043 standards, for an ILC to be valid, it must be arranged by an organization accredited by an accreditation body, known as Proficiency Testing Provider (PTP).

The PTP sets up a specific project for each test item. Each circuit, or testing cycle, is then organized logistically and shared with the participants through an activity protocol and a calendar. Finally, the PTP collects the cycle’s data, performs statistical analysis, and issues evaluations for each individual participant.

Purposes of Interlaboratory Comparisons

According to ISO/IEC 17043 standards, an ILC is conducted to:

  • Evaluate specific calibration methods and monitor laboratory performance on a regular basis.
  • Identify problems and suggest solutions related to inadequate measurement procedures, deficiencies in personnel training/supervision or in the equipment calibration.
  • Define the effectiveness and comparability of calibration methods.
  • Provide training to participating laboratories based on the results of the ILC.
  • Validate uncertainty statements and metrological traceability.

Furthermore, according to ISO/IEC 17025 standards, participation in ILCs is a mandatory requirement for obtaining and maintaining specific accreditations for testing or calibration procedures, and may also be requested by partners or customers / clients.

Conducting Interlaboratory Comparisons

ILCs are organized into schemes, which vary depending on the testing / calibration sector.

The classical scheme in the calibration field is the sequential scheme, in which one or more samples are sequentially calibrated and exchanged by participating laboratories. After the initial calibration performed by the reference laboratory, each participating laboratory performs the calibration of the sample according to their own methodologies, and then shares the results with the PTP within the specified time frame.

To participate in an ILC, a laboratory must register with an accredited PTP, according to ISO/IEC 17043 standards. Each PTP offers its own schedule of comparisons and has its own registration procedures.

SA Quality for Metrology provides a Proficiency Testing Web PortalĀ (PT Portal) where a laboratory can register for ILCs quickly and autonomously, without having to send emails with attached information and documents to the provider. In addition, through our portal, laboratories are in direct contact with the cycle coordinator and can manage comparison-related information online.


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