Write an SOP for external quality assessment procedures


As with all other procedures the procedure for participating in proficiency testing (PT) schemes and/or inter-laboratory comparison schemes and/or for organization of a rechecking/retesting system must also be standardized so that this is always done in the same, correct way. This ensures that the laboratory gets the most out of EQA and can utilize it to the maximum extent for improvement.


Document the procedure of participating in PT schemes and/or inter-laboratory comparison schemes and/or for organization of a rechecking/retesting system in an SOP. If the laboratory participates in a PT scheme the following procedures must be documented (see previous activity for an elaborate description of the different procedures):

  • Procedure for ensuring that EQA samples are analyzed in the same way as routine samples.
  • Reporting of results back to organizer of PT scheme.
  • When the final report is received from the organizer of the PT scheme, checking of correctness of results, discussion of results with laboratory staff and follow-up of incorrect results with a problem analysis to formulate corrective actions, introduce controls and possible preventive actions in the routine procedures, including adaption of SOPs of these procedures.
  • Monitoring if the problem is solved.

Ensure that the Plan-Do-Check-Act cycle is present in this procedure.

If the laboratory participates in an inter-laboratory comparison and/or has a rechecking/retesting system the same procedure as above must be followed; the laboratory must improve when incorrect results have been produced (the plan-do-check-act cycle must be followed).

If the laboratory organizes an inter-laboratory comparison itself this procedure must also be included in the SOP, including at least protocols for the following activities/items:

  • Preparation and validation of samples.
  • Blinding of samples.
  • Distribution of samples, including preparation of accompanying documents such as a guideline for reporting the results and a possible template for reporting of the results produced by participating laboratories.
  • Analysis of results reported back to you (including an analysis of variance and identification of significantly deviating results).
  • Drafting of the final report and sending this to all the participants.

If the laboratory has a rechecking/retesting system for a certain test the procedure for this also has to be included in the SOP.

How & who

Laboratory Manager:

  1. Document the procedure for participation in an EQA scheme and, if applicable, organizing the inter-laboratory comparison scheme. Follow the protocol for developing a Procedure SOP in the Master SOP and use the template of a Procedure SOP attached to the Master SOP.
  2. Review and authorize the SOP according to the SOP for Document Control.
  3. Include the SOP in the Read and Understand List and indicate which staff members have to read the SOP because its contents are relevant for their work.
  4. Present the SOP in a weekly staff meeting and indicate which staff members have to read the SOP. Explain that they have to sign the Read and Understand List after reading the SOP.

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This activity belongs to the QSE Assessment


ISO15189:2007: 4.2.1