The test items' properties and analyte concentrations are not disclosed to participants before the final report.
At the end of each round, the EQA organizer sends out reports and/or certificates to the participating laboratories.
This is because relying solely on the lab-internal quality management can create a false sense of safety.
[1] For a laboratory, gaining and keeping the ISO 17025 accreditation status is of high commercial importance.
For this reason, laboratory employees might treat EQA test items differently.
They may be handled by more experienced staff than those who examine typical routine samples, subjected to more rigorous checking procedures than normal, or results and information from other participants (collusion) may be sought before reporting.