As the Immunoserology Subcommittee of the Korean Association of External Quality Assessment, we organized two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) in 2015. For this purpose, we delivered three kinds of pooled sera specimens for external proficiency testing to 1,071 and 1,074 institutions for the first and second trials, respectively. Pooled sera were checked for their homogeneity and stability using multiple methods between the day of their manufacture and three days after dispatching. The number of participating laboratories was 1,055 (98.5%) and 1,055 (98.2%) in the first and second trial, respectively. The most commonly tested items were hepatitis B surface antigen, followed by the antibodies to hepatitis B surface antigen, anti-human immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which were found to generate few false positive results. In contrast, false negative results were frequently found when the immunochromatographic assay (ICA) was used; the use of ICA for detecting viral markers has been steadily increasing in recent years. Furthermore, the use of turbidoimmunoassay and CLIA, tests recently introduced for the measurement of non-treponemal and treponemal antibodies, is also increasing.

Keywords: External quality assessment, Hepatitis B, Hepatitis C, HIV, Immunoassay, Laboratory proficiency testing, Serology, Syphilis

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