I would like to know which is the acceptability limit of Papp of Lucifer Yellow in assessing Caco-2 cells monolayer integrity. Some authors and Corning manual cite
I don't think there is an absolute standard value. One must only qualify the lowest and highest Papp values to assert the model's dynamic range in your lab, and then ensure low well-to-well variability. If you are using LY to qualify each well for inclusion or exclusion, then you should establish what fold change constitutes an outlier relative to the cumulative historic values coming from your lab's measurements.