Syphilis Test Gives 1 in 5 a False Positive CDC recommends alternate test By Nick McMaster, Newser Staff Posted Feb 12, 2011 8:05 AM CST 7 comments Comments The dominant syphilis test is finding syphilis where there is none. (AP Photo/Jae C. Hong) (Newser) – 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.