Review of Penner's criteria for proficiency testing in cytopathology: implications for the redesign of the federally mandated proficiency testing in cytopathology.

Thirty-three years ago Penner advocated six criteria for the performance of proficiency testing in cytopathology (PTC). Since that time, several further requirements have been added by other authors. The present article critically evaluates and modifies the original criteria and adds two more principles, validity and reliability, that we recognize as crucially important in the performance of PTC.

Cytopathology proficiency testing: where do we go from here?

With the recent introduction of nationwide proficiency testing in cytopathology (PTC), reconsideration of several aspects of this controversial quality assurance method becomes justified. This paper discusses various merits and demerits of the PTC system currently prescribed by federal regulations, points out perceived deficiencies, and suggests methods for improvement.