Hepatitis B virus (HBV) is an infectious, and potentially fatal, human disease that causes serious liver disease. There are three start codons on the Gene S HBV surface protein antigen (HBsAg) that divide the gene into three sections: pre-S1, pre-S2, and S. These start sites create three carboxyl, coterminal polypeptides that are called large (LHB, the order from surface to the inside: pre-S1, pre-S2, and S), middle (MHB, containing the pre-S2 and S portion) and small (SHB, covering only the S portion). The pre-S1 amino acid region of LHBs consists of 119 amino acids and has been shown to interact with its human binding partner, γ2-adaptin, to subvert the membrane-trafficking apparatus to mediate virion export. HBsAg-PreS1 can be used for Immunochromatography, monoclonal and polyclonal antibody preparation or for ELISA analysis.