Analysis of laboratory test results of syphilis antibody from 2011 to 2016

Objective To analyze the results of syphilis serology test results among hospitalized patients, and to investigate the prevalence of syphilis. Methods The results of syphilis antibody test of 199 498 patients of Haikou People′s Hospital from 2011 to 2016 were retrospectively analyzed. All samples were screened by Treponema pallidum (TP) antibody using enzyme linked immunosorbent assay (ELISA). Syphilis toluidine red unheated serum reagin test (TRUST) was used to test nontreponemal antibody. The TP-ELISA positive samples were confirmed by Treponema pallidum particle agglutination test (TPPA). Chi-square test was used for statistical analysis. Results A total of 7 616 cases were positive of anti-TP, with positive rate of 3.82%. From 2011 to 2016, the annual cases tested were 23 188, 32 010, 35 079, 35 734, 35 406 and 38 081, respectively. The annual positive rates of anti-TP were 4.11% (952/23 188), 3.94% (1 261/32 010), 4.55% (1 597/35 079), 3.85% (1 376/35 734), 3.47% (1 229/35 406), and 3.15% (1 201/38 081), respectively, and the difference was statistical significant (χ2=108.167, P 0.05), while those among patients aged -29, -39, -49, -59, -69, -79, and ≥80 years old were statistically different (χ2=20.100, 38.387, 89.360, 75.874, 87.743, 71.035 and 30.593, respectively, all P<0.05). Conclusions From 2011 to 2016, the positive rates of syphilis is increased and then decreased. And it is significantly different among different genders and age groups. The positive rate in elderly is significantly higher. Key words: Syphilis; Antibodies; Syphilis serodiagnosis