For a diagnostic immunology program of the Korean Association of External Quality Assessment Service, two rounds of external quality assessment for hepatitis serology were conducted from 2020 to 2022. Hepatitis virus antigens and antibodies program consists of 10 test items. For the first trial, we provided four types of pooled sera specimens for external proficiency testing to 1,116 participating laboratories in the year 2020, 1,137 laboratories in 2021, and 1,146 laboratories in 2022. For the second trial, 1,101 (98.7%), 1,125 (98.9%), and 1,144 (99.8%) laboratories agreed to participate in the years 2020, 2021, and 2022, respectively. The most frequently tested items included hepatitis B surface antigen, antibodies to hepatitis B surface antigen, anti-hepatitis C virus, antibodies to hepatitis A virus, total hepatitis B envelope antigen (HBeAg), antibodies to hepatitis B envelope antigen, immunoglobulin M, and antibodies to hepatitis B core antigen. Chemiluminescence and the electrochemiluminescence immunoassay methods were most frequently used for detecting the viral markers. Until 2019, due to difficulties in pooled sera manufacturing, we used negative test results for hepatitis B envelope antibody for all evaluations. From 2020, positive test results samples were used, which improved the proficiency for test assessments of the participating laboratories. The consistency in positive test results improved due to reduced use and improved sensitivity for immunochromatography assays for HBeAg detection. The study demonstrated that the quality of viral hepatitis testing should be continuously improved by participating in the quality assessment surveys.

Keywords: External quality assessment, Hepatitis viruses, Immunoassay, Laboratory proficiency testing, Pooled serum