Rumors were running wild ahead of the UFC's big announcement (Belfort's removal/replacement with Lyoto Machida) that the actual reason Belfort was withdrawing from the bout was that he had failed his "out of competition" drug test. As he was not yet licensed by Nevada, instead simply signing a consent form for the test, the results could not be released, and could use the TRT thing as convenient cover.
Again, that talk falls firmly under the heading of "rumors," but Belfort's lawyer didn't exactly help his case when speaking with Yahoo Sports:
Yahoo Sports: Did the test that Vitor took on Feb. 7 come back with an elevated T/E ratio?
Tabachnick: The test is not relevant as Vitor is not applying for a license to fight in Nevada at this time. The reason for Zuffa replacing Vitor with Lyoto [Machida] for the May 2014 middleweight championship bout was because of the Commission's change in direction on TRT/TUE [Thursday]. Zuffa felt that with this change at the Commission, there is no time for Vitor to drop his TRT program, secure a license for a May 2014 bout and leave Zuffa with time to properly promote the bout.
If Vitor passed the test, isn't the simple answer to that question "No?"
Isn't saying the test is not relevant likely to read to most people as "yes, he failed the drug test?"
The test results will come into play should Belfort ever apply for a license in Nevada again. They're on file, just not public record at this point. But, given that he has only fought in Nevada once since October of 2006, it's entirely possible that he'll never need to apply for a license in the state again. His camp knows if there was a failure and can turn down fights there. The UFC likely also knows and can avoid even asking if they so desire.
The Belfort camp has no legal reason to, nor do they "have to." But self-releasing the results of the test are the only way that they'll erase the initial suspicions, which have only been amplified with the non-denial from Tabachnick.