Should the laboratory assess the sampling adequacy of cervical smears?

Abstract

The results of a questionnaire answered by 14 out of the 18 NHS laboratories in Scotland reporting cervical smears showed that, since the publication of Guidelines for Judging the Adequacy of a Cervical Smear, by the British Society for Clinical Cytology (BSCC), rates of unsatisfactory smears had risen from a mean of 3.3% to 6.5%, with some laboratories reporting rates of over 10%. Four laboratories followed the guidelines closely in requiring the presence of two indicators of sampling of the transformation zone, i.e. endocervical cells, metaplastic cells or endocervical mucus. Seven laboratories required one indicator either in all smears or in a subset, whilst three did not require any indicator at all. The laboratories observing the guidelines closely had a higher mean unsatisfactory rate than those partially observing them. The main impediment to the full implementation of the BSCC guidelines appeared to be fear of an unmanageably high unsatisfactory smear rate. The accuracy of the assessment of adequacy is questioned, as is the cost effectiveness of doing so.