Recall of women in a cervical cytology screening programme. An estimate of the true rate of response.

In a sample of 1007 women from a large cervical cytology screening programme in the Manchester region, the apparent response-rate to a letter inviting women to have a second routine smear three years after their first was 47-6%. After taking account of those who had become ineligible on medical grounds, or inaccessible, a conservative estimate of the true rate of response was 65-7%. When women who had had interim smears or examinations elsewhere were included, 72-2% of the original population of women had continued to make use of facilities for cytological screening.