The cervical smear test: does timing have an effect on sample adequacy?

The aim of this study was to determine the effect of timing of the cervical smear test on sample adequacy.

Inadequate and negative smears from pre-menopausal women, with a regular menstrual cycle and who were not undertaking any hormone therapy, were selected and re-screened. The inadequate smears were then categorized according to the reasons for the inadequate result. The time of the cycle that the smear was taken was recorded for both inadequate and negative smears. The expected frequency of smears per phase was compared with the observed frequency per phase using the chi-squared statistical test.

There was no significant difference between the overall observed and expected rate of the inadequate smears of nine general practitioner (GP) practices (P = 0.886), of GP practice 4 (lowest inadequate rate) (P = 0.610), or GP practice 6 (highest inadequate rate) (P = 0.621) at any phase of the cycle.

Results show that there is no optimum phase for adequate sample collection, therefore it is suggested that there is no effect of timing of the cervical smear test on sample adequacy, that timing is not a relevant factor in reducing the inadequate smear rate, and restricting smear taking to mid-cycle is unnecessary. (The information regarding last menstrual period/length of cycle from which these conclusions were reached relied upon the accuracy of patient information given to the smear taker.).