Flow cytometric DNA analysis of frozen samples

Now that flow cytometric DNA analysis is becoming an established procedure, many samples that are being received from various hospitals cannot all be analyzed within a day. Therefore, samples must be stored for subsequent analysis in a flow system. To determine a proper temperature for storage by freezing, samples of the same material were stored for 2 weeks at 5 degrees C, -80 degrees C, and -195 degrees C. Measurement and analysis at the end of this period revealed no major differences among the subsequent histograms of these samples. Thus, it seems that a flow cytometric DNA analysis can be made of frozen samples for diagnostic and prognostic evaluations.