Time interval effect on repeat cervical smear results

OBJECTIVE: Second cervical smears obtained at short time intervals often exhibit a lesser degree of abnormality than the first smear. We studied the effect of time interval between smears on diagnoses in two large, distinctive cohorts. STUDY DESIGN: Patients with two or more satisfactory smears with at least one smear or a cervical biopsy showing atypical squamous cells of undetermined significance or greater were selected. Patients were divided into four subsets by test intervals (days) (≤ 45, 46-90, 91-120, >120) and compared statistically. RESULTS: The distribution of differences between results for the short-interval subsets (<120) was significantly different (P<.01) from the interval subset >120 days. At short intervals the results revealed loss of sensitivity in the second smear as compared to the initial smear and concurrent biopsies. CONCLUSION: Rapidly repeated cervical smears show poor agreement with the biopsy and may be misleading. This effect is most pronounced when the interval is <45 days. Colposcopists should consider whether concurrent smears shortly after an abnormal smear are worth performing, given the loss of sensitivity.