18% of positive syphilis test results are false positives. The results are reported by the Centers for Disease Control and Prevention, based on a study of 5 different laboratories in the United States. The test is performed during pregnancy, planned operative interventions, and also in people at high risk of sexually transmitted diseases. When syphilis is diagnosed, penicillin is usually prescribed. The treatment has side effects in some patients, which is unjustified for people with a false positive test result. The test method for syphilis has been used since 1980. It is not yet clear to what extent its application in medical practice does not contradict other methods. That is why experts recommend to repeat the tests in cases of a positive result.