External quality assessment
|This article relies largely or entirely upon a single source. (June 2010)|
EQA is also known as proficiency testing.
EQA or proficiency testing is different from quality assurance which, in a laboratory setting, is the total process whereby the quality of laboratory results can be guaranteed.
EQA or proficiency testing (PT) is the challenge of the effectiveness of a laboratory's quality system with samples of known but undisclosed content.
PT/EQA schemes for laboratories aim to provide the laboratory management with an insight into the quality of the routine work of their laboratories. The following qualifying factors apply:
- PT/EQA results will only provide an effective insight into routine results if the PT samples are treated in the same way as routine samples.
- If PT/EQA samples are treated differently from routine samples then the PT results may be excellent but nothing will be learnt about the quality of the routine service.
There are several ways in which PT samples may be given ‘special’ treatment. 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. These practices must be discouraged by laboratory management. If the scheme organisers suspect collusion then the laboratories concerned will be contacted.
To help to prevent malpractice and in order to gain maximum benefit from PT, management are advised to deal with situations where results for PT samples are incorrect in a sensitive manner. Problems may result from general failures in the quality system rather than from errors by individual staff. If incorrect PT results are not handled with sensitivity, staff may become defensive and will make more effort with PT samples in future to avoid further criticism. It is essential to involve staff closely in the process of quality system development. A positive approach to PT will help to reassure staff.
PT/EQA is of paramount importance in food, water and medical testing where the impact of incorrect results can impact on people’s health. Many countries have organisations with a government remit to protect people’s health such as the Health Protection Agency in the United Kingdom.
A wide range of EQA schemes or proficiency testing schemes for laboratories are listed in EPTIS.