Improved flow cytometry of cellular DNA and RNA by on-line reagent addition

Acridine orange (AO) staining enables flow cytometric measurement of cellular DNA and RNA. With the conventional procedure, red and green fluorescence intensities alter considerably in time, affecting the reliability and reproducibility of the results. A standardized simple technique of AO staining is described that keeps the time between addition of detergent and AO and the subsequent measurement constant. Measurements by means of this on-line method appear to be much more reproducible in comparison to those obtained using the conventional procedure.