Papanicolaou smear adequacy: the effect of the sampling sequence.

BACKGROUND The purpose of this study was to determine the effect of ectocervical sampling methods and sequence on Papanicolaou smear adequacy. METHODS A randomized clinical trial was performed using either a curved cytologic sampling brush or Ayre spatula for ectocervical sampling before or after a straight sampling brush for endocervical sampling. RESULTS The adequacy of ectocervical smears, as measured by the presence of columnar cells or squamous metaplasia, differed significantly among the four techniques studied. When the Ayre spatula was used second, 115 (69 percent) of 167 ectocervical smears were adequate compared with 75 (48 percent) of 156 smears when it was used first. Likewise, when the curved brush was used second, 116 (67 percent) of 172 ectocervical smears were adequate compared with 80 (50 percent) of 160 smears when it was used first. One hundred ninety-six (59 percent) of 332 ectocervical smears obtained with a curved brush were adequate compared with 190 (59 percent) of 323 ectocervical smears obtained with a spatula. CONCLUSIONS The differences among the four ectocervical sampling techniques studied were due to the sequence of ectocervical sampling rather than the instrument utilized. We recommend that an ectocervical sample be obtained only after a straight brush is used to obtain an endocervical sample.