An evaluation of cytologic sampling techniques. A comparative study.

False negative cervical cytology is primarily due to errors in sampling. It has been demonstrated that combined ectocervical and endocervical sampling techniques will improve the yield. A prospective study was done to compare ectocervical and combined sampling with a selective technique in which the examiner determines the location of the squamocolumnar junction and chooses the appropriate method. The results demonstrate that combined ectocervical and endocervical sampling significantly increases the number of positive Papanicolaou smears. Selecting which cervices should be samples ectocervically and which need combined sampling does not significantly improve the yield over ectocervical sampling alone. It is the conclusion of this study that both ectocervical and endocervical sampling should routinely be used.