You have syphilis. OK, maybe not. That's the experience hundreds of people may have suffered thanks to inconsistencies in the dominant syphilis test, USA Today reports. Some 18% of people who tested positive since the 1980s were actually free of the disease, according to a study by the Centers for Disease Control and Prevention. The CDC recommends a second testing method—but doesn't have nationwide figures for how prevalent the faulty method is.
(More CDC stories.)