Membrane permeability assays only provide information about the integrity of the cell membrane, without directly assessing other aspects of cellular health, such as metabolic activity or functional status.
Temporary membrane disruption or transient changes in permeability resulting from certain experimental conditions may give false positive results.
Calcein is sensitive to buffers containing esterases
Calcein staining and propidium iodide staining cannot be combined with fixation protocols
Apoptotic cells retain their membrane integrity and are resistant to exclusion dyes.