Strategies for reducing Papanicolaou smear screening errors: principles derived from data and experience with quality control.

A number of principles pertaining to types of measurements of Papanicolaou smear accuracy are presented and implications with respect to quality control operations are explored. There are strengths and weaknesses inherent in each of the quality control methods available to us; choices regarding which of them to use and specifics regarding their implementation should be guided wherever possible by common sense and well-analyzed data as well as by regulatory requirements. Definitions of error in particular require careful attention from the points of view of both microscopic criteria and choice of reporting nomenclature. Other elements that characterize Papanicolaou smear screening environments, such as workload limits and new technologies, are also discussed.