[The effectiveness of cytology in the prevention of cancer of the uterine cervix (author's transl)].

The cytodiagnosis has become the main stay of prevention of cancer of the uterine cervix. The accuracy was once judged to be very high and is not considered to be quite as high to date. In this paper the possibilities for the development of mistakes and the type of mistakes are described, which can arise in a method which has several steps.