Women's understanding of a "normal smear test result": experimental questionnaire based study

To describe women's understanding of a negative smear test result when presented using the term "normal smear result," as required by the NHS cervical screening programme, and to evaluate the impact on understanding of different ways of presenting the residual risk inherent in such a result.

Experimental questionnaire based study.

Participants were asked to imagine that they had received a normal smear result. The meaning of this result was then presented using different combinations of three different expressions of residual risk of having or developing cervical cancer over the next five years: a verbal probability of absolute risk (low risk), a numerical probability of absolute risk (1 in 5000), or a numerical probability of risk relative to an unscreened woman (five times lower).

1027 women aged 20 to 64.

When informed only that their smear result was normal, 52% (80 of 153 women) of participants correctly understood that this entailed a residual risk of cervical cancer, compared with 70% (107 of 152) given the additional sentence explaining the meaning of a normal smear result using a verbal probability of absolute risk (difference 18%; 95% confidence interval 7% to 29%). Additionally, explaining the results using a numerical probability of absolute or relative risk did not increase the proportion who correctly understood that there was a residual risk of cervical cancer.

NHS policy for reporting normal smears needs to change to make it a definite requirement that the reporting of a "normal smear result" is accompanied by a sentence stating that this means a low risk for having or developing cervical cancer in the next five years.