Consequently, exfoliative cytologic methods are most sensitive when cellular material is obtained from this zone. The transformation zone moves upward with age, and in most menopausal women it resides in the endocervical canal. Direct exfoliative cervical samples should include the full circumference of the canal. The squamocolumnar junction may vary in location, and physicians should sample the appropriate area. The presence of endocervical or metaplastic cells in the smear indicates that the transformation zone has been sampled.
Cervical mucus is a poor indicator of transformation zone material.
However, the presence of endocervical columnar cells cannot be used as the sole criterion of an adequate Papanicolaou smear, as it does not guarantee that a good circumferential smear has been obtained. Furthermore, if devices for obtaining samples from the endocervical canal are improperly used, obscuring blood and uninterpretable thick cellular fragments can result in suboptimal smears. Smears composed mainly of endocervical cells may be a poor sampling of the transformation zone if a large ectropion is present. An information system in which smear results are recorded allows comparison of a current smear with previous smears, and the sampling of the transformation zone can be traced over successive smears. To determine the adequacy of Papanicolaou smears, we make the following recommendations.