Yes in my investigations, I have also found these guidelines but thank you for the link. And your point is absolutely right about the number of lows known to exist - how long is a piece of string. I mean in our particular procedure it even says to test against SARA, which is just crazy considering that there are only a handful of people that have this low incidence antigen. That's why the more I think about it, the more I'm inclined to think that someone just selected some random low incidence antigens to throw in the procedure. But with the crazy amount of regulation in our company now, to modify this procedure is extremely difficult as you have to confront a panel of 10 control members (most of which lack any sort of blood banking knowledge) and have one moron disagree with you to get your change thrown out and have to restart you justification.