Though it's not in the ED guidelines, it's a part of the general Bluelight user guidelines that we don't allow drug testing posts. I've let a few fly, but eventually they get closed up.
You'll find this is a topic with a lot of rumors and misinformation- if you are confident a drug test may happen Monday, it's likely a bad idea to chance the results by using MDMA 72 hours beforehand. I'd do as much research as possible if you are going to make the decision to use MDMA within a few days of a drug test.