Yep. My carry-on was swiped and came back positive. The agent asked, and I replied that I had just taken my blood pressure medication. He said, "Yep, this was it."

A little OT, but, years ago - before 9/11, I did weapons testing for the US government and sometimes had to run to the airport to make my return flight. Often, I was covered with explosives residue (as were my cases carrying testing equipment). Today, I guess I would be branded a terrorist.