Temporal characteristics of laboratory screening errors in cervical cytology

OBJECTIVE: To explore the temporal characteristics of laboratory false negative reports in cervical cytology. STUDY DESIGN: The temporal characteristics of 198 false negative cervical cytology cases were compared with those of 750,805 control cases. RESULTS: The false negative rate did not vary significantly by month, day of the week or time of day. The false negative rate was lowest for slides that took between 4 and 5 minutes to screen and increased significantly with screening times that were longer than 5 minutes. The false negative rate did not vary by the number of cases already authorized in a given day. After 40 cases had been authorized in a given day, the false negative rate fell for subsequent cases, but this did not reach statistical significance. The false negative rate was higher during periods when prescreening was performed. CONCLUSION: Further studies of the relationship between time and false negative reports are needed. These would provide an evidence base to help promote safe working practices within laboratories and a more objective setting of maximum daily productivity levels for cytotechnologists.