Hepatitis B Surface Antigen (Hbsag) Assays--Are They Good Enough for Their Current Uses?(Editorial‪)‬

Hepatitis B virus (HBV) is the most common significant chronic viral infection world-wide. Approximately 350-400 million people have active HBV infections, and as many as one third of the world's population has evidence of exposure to HBV. Spread of the virus occurs primarily through contact with infected serum, sexual contact with infected individuals, and vertical transmission from mother to infant. Since shortly after its discovery as the "Australia antigen" (1), hepatitis B surface antigen (HBsAg) has been the principal target for laboratory testing to identify active infection by HBV. Accumulating evidence, including the article by Chen and Kaplan (2) in this issue of Clinical Chemistry, calls into question the degree to which HBsAg assays can be used as the "gold standard" for detecting HBV infection. The increasing availability of automated assays for viral markers on instruments traditionally found in immunochemistry laboratories makes it imperative for those working in such laboratories to be familiar with issues in HBsAg testing. NATURAL HISTORY OF HBV INFECTION