The two will headline a Dec. 15 show, The Ultimate Fighter 16 finale, from the Hard Rock Hotel & Casino in Las Vegas. That card airs on FX.
Commission Executive Director Keith Kizer confirmed both fighters were tested for anabolic steroids and diuretics, and also noted that unlike a lot of fighters, when asked, both made it clear they were very happy to be tested.
"I called Shane the morning of the 18th, and he went right in (to the lab) right then and there," said Kizer. "I talked to Roy late on the 18th, and he went in first thing the next morning.
"Both were extremely happy to go. I had a similar experience when I talked with (Jorge) Gurgel and (Joe) Duarte at Strikeforce a couple of years ago (a fight in August 2011). It's not always the reaction. I've never had a negative reaction, but they were actually pleased to get tested."
Nelson (17-7) had pushed for outside testing of both he and Carwin in the weeks leading to the fight by the Voluntary Anti-Doping Agency. Carwin (12-2), a former No. 1 ranked heavyweight contender, turned it down, with his management claiming the VADA web site had a negative article on him and questioned them being unbiased. Nelson, who has been outspoken about performance enhancing drugs in MMA, claiming that a number of his previous opponents were using, then enrolled on his own.
Nevada has funding for some testing of both boxers and MMA fighters out of competition. Headliners are often given surprise tests during training camp. All main event fighters and several other fighters chosen at random are tested the night of the fight.
The results of the testing just came in, as Kizer said they were delayed by about ten days due to Hurricane Sandy.