ABSTRACT
BACKGROUND: The Korean Red Cross blood laboratory centers use Treponema pallidum particle agglutination assay on the PK7300 instrument as a primary donor screening test for syphilis, and semi-quantitative TPPA and RPR card as supplementary tests. We compared the results of Treponema pallidum latex agglutination and RPR tests on the automated analyzer with those of TPPA and RPR card tests. METHODS: A total of 1,000 samples with negative TPPA results and 103 samples with positive TPPA results (> or =1:80 titers) were evaluated in this study. HiSens Auto TP, RPR (HBI, Anyang, Korea) and Mediace TPLA, RPR (Sekisui, Tokyo, Japan) reagents were used on the automated analyzer. FTA-ABS test was performed as a confirmatory test to evaluate the sensitivity and specificity of HiSens Auto TPLA, RPR and Mediace TPLA, RPR reagents. RESULTS: The concordance rate between HiSens Auto TP, Mediace TPLA and TPPA was 95.5% and 95.4%, respectively. The concordance rate between HiSens Auto RPR, Mediace RPR and RPR card was 79.6% and 80.6%, respectively. Sensitivity of HiSens Auto TP and Mediace TPLA was 87.7% and 90.8%, respectively, and specificity was 99.5% and 99.0%, respectively. CONCLUSION: Despite the high concordance rate between TPLA and TPPA, there were negative TPLA results which were positive for both TPPA and FTA-ABS tests. Therefore, changing the primary donor screening test for syphilis from current TPPA to TPLA on the automated analyzer requires further investigation.