[Significance of sources of error and quality control in cytologic mass screening].

The cervical mass screening programme in the GDR (since 1973) indicates a high degree of participation exhibiting a sufficient specificity. The sensitivity however has to become better. The main cause of false negative diagnoses is the insufficient gaining materials from the endocerrix channel. This may be corrected by a new plastic spatula. Both the consequent education of the prescreeners and collective final diagnoses may give further help to reduce cytological false negative diagnoses. False positive diagnoses are less fatal. They may be corrected by repeated controls, by special consultations, and by histology.