Propidium Iodide Technical Points Propidium Iodide Ploidy Analysis Technical Points 1. It is often necessary to try more than one technique before finding the one that will work best with your cells.
Some cell types tend to clump during the propidium iodide staining procedure.
If cell clumps are present, there is a good possibility that the cells cannot be analyzed since they will clog the sample intake line of the flow cytometer. You should always examine at least one of your sample tubes prior to bringing them to the FACS lab to see if clumping is present. If the cells you are working with are adherent cells and you are using trypsin to detach them from culture dishes, you should not let these cells stay in the presence of trypsin for any length of time longer than necessary.