Internal quality control in an academic cytopathology laboratory for the introduction of a new reporting system for endometrial cytology.

Application of appropriate statistical tests shows that integration of a new reporting cytologic system is effective with an overall accuracy around 90%. Both statistical tests applied disclosed lower agreement rates among both all five raters and the three most experienced ones in the intermediate categories constituting the gray zone, thus delineating the need for better training of cytopathologists to correctly identify diagnostic criteria for classification of a given case into these categories.