The six fighters who showed up to help promote UFC 146 on Tuesday were surprised by the Nevada State Athletic Commission with an on-site drug test. News of the testing was first reported by Ron Kruck of “Inside MMA.”

Heavyweights Junior dos Santos, Alistair Overeem, Cain Velasquez, Frank Mir, Antonio Silva and Roy Nelson were also given tests by NSAC executive director Keith Kizer following the press conference. Kizer explained the decision to MMA Fighting’s Mike Chiappetta.

We brought the drug test to them instead of making them go to the drug test. If they were not in Las Vegas, I would need to find them a lab, which is of course, much more of a hassle.

This was the first time NSAC has performed such a test in MMA, though they did do the same thing to boxers Abner Mares and Joseph Agbeko last August.

UFC 146 is set for May 26. Kizer added that the results may not become available to the public before that date. However, if someone tested positive, that likely would become public knowledge.