Hepatitis B surface Antigen (HBsAg) and hepatitis C antibody (anti-HCV) assays have been performed in most laboratories using a variety of analytical methods with different reagents for Hepatitis B virus (HBV) and Hepatitis C virus (HCV) screening [1][2] . The purpose of this study was to develop an EQA program for dual HBsAg and anti-HCV serological testing to ensure the accuracy and reliability of serological assays. A serum panel of 12 samples containing three negative, three positives for each virus and three positives for both of HBsAg and anti-HCV. These panels were distributed to 102 laboratories in the South of Vietnam. They were required to report their results and any problems encountered on EQA panel. The results show that performance of HBsAg and anti-HCV tests is not only different in terms of method used but also in the types of biological products. Rapid tests (RTs) to detect HBsAg and anti-HCV were most commonly used to screen for HBV and HCV in laboratories. The coincidence rates of RTs for HBsAg and anti-HCV serological assays were 88.24% and 89.86% respectively, while electrochemiluminescence (ECLs) and chemiluminescent immunoassays (CLIAs), Enzymelinked immunosorbent assay (ELISA) showed the best performance for both HBsAg and anti-HCV testing. The most challenging was failed to detect weak positive samples. In conclusion, the differences in test results within and between groups of HBsAg and anti-HCV assay methods indicated a need to improve test conditions at laboratories in Viet Nam.

Hepatitis B surface Antigen (HBsAg) and hepatitis C antibody (anti-HCV) assays have been performed in most laboratories using a variety of analytical methods with different reagents for Hepatitis B virus (HBV) and Hepatitis C virus (HCV) screening [1][2] . The purpose of this study was to develop an EQA program for dual HBsAg and anti-HCV serological testing to ensure the accuracy and reliability of serological assays. A serum panel of 12 samples containing three negative, three positives for each virus and three positives for both of HBsAg and anti-HCV. These panels were distributed to 102 laboratories in the South of Vietnam. They were required to report their results and any problems encountered on EQA panel. The results show that performance of HBsAg and anti-HCV tests is not only different in terms of method used but also in the types of biological products. Rapid tests (RTs) to detect HBsAg and anti-HCV were most commonly used to screen for HBV and HCV in laboratories. The coincidence rates of RTs for HBsAg and anti-HCV serological assays were 88.24% and 89.86% respectively, while electrochemiluminescence (ECLs) and chemiluminescent immunoassays (CLIAs), Enzymelinked immunosorbent assay (ELISA) showed the best performance for both HBsAg and anti-HCV testing. The most challenging was failed to detect weak positive samples. In conclusion, the differences in test results within and between groups of HBsAg and anti-HCV assay methods indicated a need to improve test conditions at laboratories in Viet Nam.