Six UFC heavyweights got a surprise on Tuesday when the Nevada State Athletic Commission came calling after the group had spoken to fans and media about their upcoming bouts at UFC 146. According to multiple reports, rather than request paperwork or address something specifically related to the respective match-ups, the regulatory board randomly tested the fighters for drug use.

Included in the sextet of scrappers were headliners Junior dos Santos and Alistair Overeem, as well as Frank Mir, Cain Velasquez, Roy Nelson, and Antonio Silva.

Inside MMA’s Ron Kruck was the first person to report the testing had taken place.

Unrelated to his peers, the screening was the first of two Overeem will undergo prior to the May 26 main event as a condition he agreed to in order to fight Brock Lesnar in late December. The 31-year old missed a required deadline leading up to the contendership-sealing bout, thus leading to the special arrangement.

None of the fighters except Silva have ever been popped for illegal drugs. The Brazilian’s transgression came in 2008 stemming from a testosterone booster used to treat his acromegaly. As a result he was suspended for a year though still chose to fight in Japan during the period.

No word has surfaced on when the results from this week’s test will be made available to the public.