Figure II-1-1. Development of T-ZoneStudies show that while the “liquid-based” methods reduce the percentage of
unsatisfactory specimens as compared with the “traditional” method, both
methods are equivalent in performance for detection of cervical dysplasia.
With traditional Pap smear, samples are obtained using a wooden spatula
on the ectocervix and a Cytobrush for the endocervical canal rotating in one
direction 360°. The cells from each area are then smeared evenly onto a glass
slide, which is then fixed in formalin and then stained and examined under a
microscope by a cytologist. Potential problems include insufficient smearing
of all abnormal cells onto the glass slide, air drying artifacts if fixing is
delayed, and clumping of cells, making cytology assessment difficult.
With liquid-based Pap smear, specimens are obtained using a cervical
broom. Long central bristles are placed into the endocervix and short outer
bristles over the ectocervix. The broom is rotated 5 times in the same
direction, collecting and sampling both endocervical cells and transformation
zone. The cervical broom is placed in the preservative solution and rotated 10
times vigorously to release collected material into the solution. Advantages
include a lower chance of abnormal cells being discarded with the collecting