Improving syphilis screening in deceased organ donors

BACKGROUND: Current U.S. policy requires screening of all deceased organ donors for syphilis infection. To date, information on syphilis test performance in this population is limited. METHODS: All donors with a positive rapid plasma reagin (RPR) and matched donors with negative RPR who were evaluated by one organ procurement organization from January 1, 2000, to September 30, 2012, were retrospectively tested, using retained, residual serum, with two alternate RPR tests and four treponemal-specific tests: A fluorescent treponemal antibody absorption test, a microhemagglutination test, a chemiluminescence immunoassay (CLIA), and a Treponema pallidum particle agglutination (TP-PA) test. RESULTS: Thirty-two of 3,555 (0.9%) potential deceased organ donors screened during the study period showed a positive RPR; 61 RPR-negative matched donor samples were studied as well. Thirteen (40.6%) of the RPR-positive donors were found to be false-positive based on confirmatory TP-PA. As compared to TP-PA, the sensitivity of the fluorescent treponemal antibody absorption, microhemagglutination, and CLIA was 87.5%, 91.7% and 100%, respectively. The CLIA and TP-PA results were 100% concordant. Only 17 (53.1%) of the RPR-positive donors had a total of 46 organs recovered for transplantation. CONCLUSION: Current screening of deceased organ donors by RPR yields a significant number of false-positive results. Use of alternative tests or the routine use of confirmatory tests may reduce the frequency of false-positive results in deceased organ donors.