One of the "conditions" of Alistair Overeem's conditional license granted by the Nevada State Athletic Commission was for him to not only re-submit his urine sample prior to leaving Holland, but to be tested again upon landing in the U.S. for the event. According to ESPN, that urine sample was taken on Monday but the results won't be known until after the fight.

From the article:

After arriving in Las Vegas on Monday, UFC 141 headliner Alistair Overeem submitted a urine sample at a Quest Diagnostics facility, per the terms of his conditional license issued by the Nevada State Athletic Commission on Dec. 12.

Results of the urinalysis aren't expected to be known by the time Overeem is scheduled to fight Brock Lesnar at the MGM Grand Garden Arena on Friday, NSAC executive director Keith Kizer told ESPN.com.

Overeem will also be tested twice randomly within six months as the remaining part of his conditional license.

SBN coverage of UFC 141: Lesnar vs. Overeem