MMWR: Discordant Results From Reverse Sequence Syphilis Screening - Five Laboratories, United States, 2006-2010

This report describes tests of an analysis of data from five laboratories that used reverse sequence screening during 2006-2010 to identify persons with possible untreated syphilis. Three sites served patient populations with low prevalence of syphilis, and two sites served patient population with high prevalence. The results indicated that among sera reactive on initial screening with an automatable treponemal enzyme and chemiluminescence immunoassays (EIA/CIA), 56.7 percent had a nonreactive rapid plasma regain (RPR) test.