Controls in quality assessment in gynecologic cytology: A rational approach to workload limits for the ThinPrep...

Major components of good quality assurance (QA) in cytology laboratories are measuring the screening accuracy of cytotechnologists (CTs) and determining appropriate workload limits for them. Currently, the FDA approved workload limits for image assisted Paps, however, are too high. In addition, the CLIA 88 mandated QA measures, by themselves, are insufficient to accurately measure the screening performance of CTs. Although the use of "controls" is fundamental to good practice in the clinical laboratory; this has not been emphasized in gynecologic cytology. In this review, we underscore the importance of using controls, such as monitoring morning and afternoon abnormal rates, in assessing CT performance and assigning reasonable workload limits. Using controls, however, requires significant alteration in the laboratory workflow, and much lower and variable workload limits for CTs, compared to those approved by FDA.