The 2018–2019 surveys on the external quality assessment scheme for serologic tests for syphilis in Korea were conducted by the Korean Association of External Quality Assessment Service. Proficiency testing (PT) panels consisting of three pooled serum samples were shipped to 586 and 589 laboratories participating in the program in the first and second trials of 2018 and 592 and 587 laboratories in the first and second trials of 2019, respectively. The rates of returning results for nontreponemal and treponemal tests were 89.6% and 43.9% in the first trial of 2018 and 89.3% and 43.5% in the second trial of 2018; 90.7% and 43.2% in the first trial of 2019 and 91.5% and 43.8% in the second trial of 2019, respectively. The most commonly used nontreponemal tests were rapid plasma reagin (RPR) card test, followed by RPR turbidimetric immunoassay, and Venereal Disease Research Laboratory tests. The most commonly used treponemal tests were Treponema pallidum particle agglutination, followed by immunochromatographic assay, chemiluminescence immunoassay, T. pallidum latex agglutination, and fluorescent treponemal antibody absorption tests. In 2018–2019, the overall accuracy rates of nontreponemal and treponemal tests were 99.0%–100.0%, significantly higher than the 92.5%–100.0% in 2017. In 2017, standard materials were made by pooling samples obtained from many patients, whereas in 2018–2019 they were made by pooling samples from a small number of blood donors. Based on these data, we recommend using pooled samples obtained from a smaller number of donors as standard materials for syphilis serology PT to minimize the matrix effect.

Keywords: External quality assessment, Proficiency testing, Serology, Syphilis