As you see from the posts here, there are various opinions of what to do.
Correct =The regulatory agencies do state to run some sort of controls, etc.
You are in charge, therefore you do what you believe is best within the guidelines when there are gray areas like this. If you believe you should change the protocol to 'QC for the Antigen', then do that.
Validation? You have criteria, I'm sure, for the cells passing inspection for use. I venture to say that most hospitals don't keep reagent RBCs more than a month or two past their outdate. It would be interesting to hear about that. If you are running QC for the tested antigen 'Day of Use', that's your validation that the cell is still working for your purpose. (I maintain that 'validation' is needed for situations where QC is not going to be run, e.g. You validate the time a box will hold a temperature so you don't have to take the temperature every time.)
We do validate that a new panel is ok by running QC Antisera with them when they arrive. I've had inspectors tell me I must do this and I've had inspectors tell me to stop. Hmmm … I do what I am comfortable with, i.e. err on the side of caution.
We don't use outdated panels … too many issues.