Is the proficiency test in cervical cytology proficient?

Leaders Is the proficiency test in cervical cytology proficient? It is accepted that internal quality control and external quality assurance are necessary elements in ensuring high standards in the reporting of cervical smears. A major component of external quality assurance in the United Kingdom in recent years has been the proficiency test in cervical cytology. Participation in regional proficiency test schemes was recommended for all staff in recently published documents concerned primarily with internal quality control in cytology laboratories.' 2 Furthermore , the working party assessing quality assurance guidelines for the cervical screening programme used participation and acceptable performance in the UK proficiency test scheme as a measure of its objective "to ensure that all staff screening or reporting smears are competent".3 The combined weight of these authoritative documents suggests that the rationale for proficiency test must be beyond question. However, at a time when proficiency test is under review, both in the United Kingdom and the United States, it may be worth considering the evidence that proficiency test actually improves laboratory performance. The regional proficiency test schemes in the UK have evolved from a protocol published in 1988 under the auspices of the Department of Health Advisory Committee on Assessment of Laboratory Standards.4 This document referred to the successful proficiency test programmes operational in North America, and commented that the protocol UK test was based on the New York Proficiency Test Scheme (NYPTS). It should be emphasised, however, that there are significant differences between the NYPTS and the UK proficiency testing programmes. The test slide set in the NYPTS comprises only one element of the proficiency testing scheme, the others, which are arguably more important, being laboratory inspection and an educational programme, more analogous to clinical pathology accredita-tion and circulating slide sets, respectively, in the UK.'-' In addition, the examination itself differs from those in the UK by including non-gynaecological material (comprising 50% of the test set since 1982).7 Furthermore, the testing mechanism does not necessarily involve all reporting staff. Only one pathologist need review the slides in each laboratory, these being pre-assessed and marked by the cytotechnol-ogy staff. The rationale of this approach is to mimic daily practice as closely as possible and the laboratory performance is judged on the final diagnosis offered by the pathologist. It is of course debatable whether the UK programmes offer an improvement on the NYPTS but comparison of data is of doubtful …