An automated initial screening of cervical smears would be of great benefit as much time would be saved by removing the need to rely on cytologists for the diagnosis of negative smears. The computerized evaluation of DNA histograms obtained by impulse cytophotometry shows promise but the additional determination of the amount of lysine in the nucleus would seem to be of value. Three mathematical methods for the evaluation of histograms are presented and compared. It is shown that measurements of nuclear DNA as well as lysine improve the diagnostic accuracy of automated screening processes.