College of American Pathologists
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  Unsatisfactory Pap reporting rates


CAP Today




August 2009
Cytopathology Programs Review

Roger B. Lane Jr., MD

The CAP assesses laboratory practice patterns using questionnaires sent to laboratories that participate in CAP programs, providing a valuable tool to investigate the self-reported practices of laboratories in the United States. The re­sults of these questionnaires have led to benchmarking data for quality as­surance purposes and for use in the CAP Laboratory Accreditation Program checklists. A new study by Ann Moriarty, MD, et al., evaluates Pap test practices and unsatisfactory rates for laboratories responding to the 2007 CAP supplemental questionnaire, which was sent to all laboratories enrolled in the 2006 CAP Interlaboratory Comparison Program in Gynecologic Cytology (Unsatisfactory reporting rates: practices of participants in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology. Arch Pathol Lab Med. In press.)

Unsatisfactory rates for Pap tests have been published since 1992, when the Bethesda reporting system was new and conventional smears were the predominant Pap test method. At that time there was a lack of standardized criteria for assessing Pap test adequacy. A previous CAP supplemental questionnaire was circulated in 2003, shortly after the newly defined Bethesda System criteria for adequate cellularity were introduced, at a time when liquid-based preparations were starting to be used more frequently for Pap tests. Results at that time showed that during the period from 1992 to 2003 unsatisfactory rates for Pap tests remained relative­ly stable, at about 0.2 percent to 0.5 percent.

The new study by Moriarty, et al., examines data from 2006, a time when standardized criteria for adequate cellularity had time to be more widely adopted and liquid-based preparations had become the predominant method for Pap tests. Overall unsatisfactory rates for Pap tests were determined along with the reported causes of unsatisfactory specimens. In addition, unsatisfactory rates and causes for unsatisfactory specimens were compared for conventional smears versus liquid-based specimens (ThinPrep and SurePath).

Results from the 2007 survey showed that the percentage of laboratories using the Bethesda System for reporting Pap tests increased from 85.5 percent in 2003 to 97.8 percent in 2006 and that 94.5 percent of laboratories use the Bethesda criteria for specimen adequacy. Interestingly, the 2007 survey showed that the median unsatisfactory rate had increased over previous surveys, but remained at 1.1 percent or less for all preparation methods. Low squamous cellularity was the most common cause of unsatisfactory Pap tests regardless of the preparation used, and air-drying was the least common cause of unsatisfactory Pap tests for liquid-based preparations.

The study by Moriarty, et al., discusses these findings and others in detail, including possible misuse of Bethesda critera for post-irradiation and atrophic preparations as well as the lack of significant effect of laboratory volume on unsatisfactory rates. This article is an excellent example of how CAP questionnaires can be used to provide valuable benchmarking data for laboratory use in quality assurance practices.

Dr. Lane, a member of the CAP Cytopathology Committee, is a pathologist with Southeastern Pathology Associates, Brunswick, Ga.