Hepatitis B Virus Large Protein, the hepatitis B surface antigen, is a marker of hepatitis B virus infection. It is also known as Hepatitis B Virus Large Protein because Hepatitis B Surface Antigen is a protein, a protein with a relatively large molecular weight. Hepatitis B Virus Large Protein is negative for Hepatitis B Surface Antigen, and in most cases, negative means that the body is not infected with the Hepatitis B virus. Hepatitis B Virus Large Protein is the most important item in the Hepatitis B 2.5 test. In a special case, if the infected hepatitis B virus has mutated and is unable to synthesize the hepatitis B virus large protein on its own, it is also possible to be negative for the hepatitis B virus large protein. In this case, the DNA of the hepatitis B virus can be detected and may be accompanied by a positive hepatitis B core antibody.