Background

To obtain an adequate cervical (Papanicolaou) smear, the transformation zone, including the squamo-columnar junction, should be sampled as carcinoma develops preferentially in this transformation zone. The Ayre spatula has been widely used but is not very effective. Other sampling devices have been developed to improve efficiency, including the cytobrush. The purpose of this study was to compare the adequacy of cervical smears taken with the Ayre spatula as opposed to the cytobrush.

Methods

This was a retrospective analytical study. One sampler, an experienced general practitioner, took the smears in the period 1990 to 2004. Initially, the Ayre spatula was used to consecutively sample the cervix and thereafter, a cytobrush alone was used. Two groups were thus formed for comparison. The presence of endocervical cells was accepted as an indicator of an adequate smear. A Cusco speculum was used to visualize the cervix. The sample was smeared onto a slide and fixated with an alcohol aerosol spray.

Results

A total of 4561 smears were taken and 247 had no endocervical cells. A further 34 smears were classified as unsatisfactory due to the presence of degeneration (19), insufficient squamous cells (7), inflammatory exudate (4), excess blood (3) and/or a thick slide (1). The cytobrush group was similar demographically to the Ayre spatula group: 1981 (99%) and 2490 (98%) respectively were non pregnant; 67 (3%) and 110 (4%) were nulliparous, 1008 (50%) and 1370 (54%) were para 1–5, and 931 (46%) and 1075 (42%) were para 6 or more; 0 (0%) and 2 (0.1%) were aged between 10–19 years, 1496 (75%) and 2012 (78%) between 20–49, and 510 (25%) and 541 (21%) were aged 50 years or more. Of 2006 smears taken with a cytobrush, 1955 (97.5%) contained endocervical cells compared with 2325 (91%) of 2555 smears taken with an Ayre spatula. The difference was significant with an Odds Ratio of 4.56 (95% Confidence Interval 3.42–6.42).

Conclusion

The cytobrush is significantly more efficacious than the Ayre spatula in obtaining adequate cervical smears. Use of the cytobrush will ensure less repeat smears with a consequent reduction in workload for samplers and laboratories. Although very few smears lacked sufficient squamous cells (an indicator of adequate ectocervical sampling), current best practice is that the cytobrush be used together with a wooden spatula to ensure adequate sampling of both the endocervical and ectocervical components of the transformation zone.