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) (< or = 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.