A rumor popped up on twitter and some forum sites last night that a fighter had failed a drug test for UFC 156. After a few inquiries last night made it seem like there may be some truth to the story, Keith Kizer of the Nevada State Athletic Commission (NSAC) has confirmed to Bloody Elbow that all fighters on the card did pass the NSAC administered urine tests.
Alistair Overeem fought on the card, his first fight since failing a test ahead of a bout with Junior dos Santos last year -- a failure which forced the cancellation of the bout and resulted in Overeem's suspension. Kizer confirmed with me that Overeem was given a blood test to check testosterone levels..etc. as well as the urine test. The results of that blood test will likely not come back until next week at some point.
But, to officially shut down the rumor, all fighters on the UFC 156 card were given the standard NSAC urine test and all passed.
Update: To be clear, the test administered to Overeem is not a Carbon Isotope Ratio (CIR) test. It's a basic testosterone level check from my understanding which means it's far from the most comprehensive type of blood testing to catch the majority of possible methods of doping.