Abstract: Objective To assess the performance capability of syphilis serology among STI laboratories in Guangdong Province. Methods Positive and negative sera samples were prepared and delivered to STI laboratories. Non-treponemal and treponemal quantitative and qualitative tests were performed with these samples based on standardized procedures. Quality and proficiency of syphilis serology among these laboratories were evaluated. Results A total of 225 STI laboratories in Guangdong Province participated in this survey, 3696 serological tests for syphilis were performed from 2004-2006. The outcomes showed that the total reproducibility among participating laboratories increased from 82.5% in 2004 to 90.0% in 2006 （χ2 = 16.8, P < 0.05）, and the percentage of laboratories with a performance level higher than the provincial average level rose from 64.7% in 2004 to 76.8% in 2006. The total reproducibility was 95.5% for non-treponemal qualitative tests，95.0% for treponemal qualitative tests, 82.1% for non-treponemal quantitative tests, and 81.1% for treponemal quantitative tests. The false-negativity and false-positivity rates were 4.7% and 4.0%, respectively, for non-treponemal qualitative tests, and 7.2% and 0.4%, respectively, for treponemal qualitative tests. Conclusions It is important to do capability building and improve the performance of STI laboratories, in order to prevent and control syphilis.

Key words: Sexually Transmitted Infections, Laboratories, Syphilis, Serological Test, Proficiency of Test