What was your exposure?
it could be anything .the test tubes have expiration dates if they forgot to check it the lab may have caught it and denied the sample .or maybe they did a cnc and saw something they were interested in .if the blood was drawn near the weekend the sample could have gone bad if no one was there to collect it until monday morning.its much too hard to speculate could be anyone of infinite possibilities .did you have a risk?
I do have a risk, I hooked up with a guy (which was a mistake) and he ejaculated into my mouth without warning me. It wasn't in my mouth very long, it freaked me out so I spit it out almost instantly. When I asked him when the last time he had a STD test was his response was "I don't need one because I'm not a ****". He also said that I'm the only person he's had sex with in months, but that statement freaked me out a little bit, so I decided to get tested.