Difficulty interpreting results due to unknown effects of fixation and permeabilization on fluorescence intensity and population distribution. Unable to distinguish artifacts from true biological changes.
Common Causes
1Failure to include unfixed controls to assess fixation-induced fluorescence changes
2No comparison between different permeabilization methods
3Lack of isotype or negative controls processed with same fixation protocol
4Incomplete validation of fixation/permeabilization effects on specific fluorophores
Solutions
1Include controls for fixation/permeabilization effects in every experiment
2Run parallel samples with and without fixation to assess fluorescence shifts
3Test multiple permeabilization conditions with appropriate controls
4Document fixation/permeabilization impact on each fluorophore in the panel